Revert "Update Xcode SDK to 12B5025f"

This reverts commit e5f1f5877073a557c1ceea43a73d1cc343e2d3a7.

Reason for revert: This requires macOS 10.15 but we only have 10.13.

Original change's description:
> Update Xcode SDK to 12B5025f
>
> Change-Id: I8203eb2093d76e4e8a23cf5090dcd258a4526e4e
> Reviewed-on: https://gn-review.googlesource.com/c/gn/+/10183
> Reviewed-by: Scott Graham <scottmg@chromium.org>

TBR=phosek@google.com,scottmg@chromium.org,dpranke@chromium.org,dpranke@google.com

Change-Id: I5f185b44b475c622fdb10f48dcaa3f18949f2f38
No-Presubmit: true
No-Tree-Checks: true
No-Try: true
Reviewed-on: https://gn-review.googlesource.com/c/gn/+/10200
Reviewed-by: Petr Hosek <phosek@google.com>

infra/recipe_modules/macos_sdk/__init__.py

diff --git a/infra/recipe_modules/macos_sdk/__init__.py b/infra/recipe_modules/macos_sdk/__init__.py
index 56b6a94..f749bfd 100644
--- a/infra/recipe_modules/macos_sdk/__init__.py
+++ b/infra/recipe_modules/macos_sdk/__init__.py
@@ -34,11 +34,11 @@
             ),
             default={
                 'sdk_version':
-                    '12B5025f',
+                    '10b61',
                 'tool_package':
                     'infra/tools/mac_toolchain/${platform}',
                 'tool_version':
-                    'git_revision:e9b1fe29fe21a1cd36428c43ea2aba244bd31280',
+                    'git_revision:434f5462a77e7103f9d610fa5cabc426bb21502e',
             },
         )
 }

infra/recipe_modules/macos_sdk/examples/full.expected/mac.json

diff --git a/infra/recipe_modules/macos_sdk/examples/full.expected/mac.json b/infra/recipe_modules/macos_sdk/examples/full.expected/mac.json
index 1fb8aba..e2acecd 100644
--- a/infra/recipe_modules/macos_sdk/examples/full.expected/mac.json
+++ b/infra/recipe_modules/macos_sdk/examples/full.expected/mac.json
@@ -6,7 +6,7 @@
       "-root",
       "[CACHE]/macos_sdk",
       "-ensure-file",
-      "infra/tools/mac_toolchain/${platform} git_revision:e9b1fe29fe21a1cd36428c43ea2aba244bd31280",
+      "infra/tools/mac_toolchain/${platform} git_revision:434f5462a77e7103f9d610fa5cabc426bb21502e",
       "-json-output",
       "/path/to/tmp/json"
     ],
@@ -17,7 +17,7 @@
       "@@@STEP_LOG_LINE@json.output@  \"result\": {@@@",
       "@@@STEP_LOG_LINE@json.output@    \"\": [@@@",
       "@@@STEP_LOG_LINE@json.output@      {@@@",
-      "@@@STEP_LOG_LINE@json.output@        \"instance_id\": \"resolved-instance_id-of-git_revision:e9b\", @@@",
+      "@@@STEP_LOG_LINE@json.output@        \"instance_id\": \"resolved-instance_id-of-git_revision:434\", @@@",
       "@@@STEP_LOG_LINE@json.output@        \"package\": \"infra/tools/mac_toolchain/resolved-platform\"@@@",
       "@@@STEP_LOG_LINE@json.output@      }@@@",
       "@@@STEP_LOG_LINE@json.output@    ]@@@",
@@ -33,7 +33,7 @@
       "-kind",
       "mac",
       "-xcode-version",
-      "12b5025f",
+      "10b61",
       "-output-dir",
       "[CACHE]/macos_sdk/XCode.app"
     ],

infra/recipes/gn.expected/ci_mac.json

diff --git a/infra/recipes/gn.expected/ci_mac.json b/infra/recipes/gn.expected/ci_mac.json
index 03d5da6..707406d 100644
--- a/infra/recipes/gn.expected/ci_mac.json
+++ b/infra/recipes/gn.expected/ci_mac.json
@@ -95,7 +95,7 @@
       "-root",
       "[CACHE]/macos_sdk",
       "-ensure-file",
-      "infra/tools/mac_toolchain/${platform} git_revision:e9b1fe29fe21a1cd36428c43ea2aba244bd31280",
+      "infra/tools/mac_toolchain/${platform} git_revision:434f5462a77e7103f9d610fa5cabc426bb21502e",
       "-json-output",
       "/path/to/tmp/json"
     ],
@@ -106,7 +106,7 @@
       "@@@STEP_LOG_LINE@json.output@  \"result\": {@@@",
       "@@@STEP_LOG_LINE@json.output@    \"\": [@@@",
       "@@@STEP_LOG_LINE@json.output@      {@@@",
-      "@@@STEP_LOG_LINE@json.output@        \"instance_id\": \"resolved-instance_id-of-git_revision:e9b\", @@@",
+      "@@@STEP_LOG_LINE@json.output@        \"instance_id\": \"resolved-instance_id-of-git_revision:434\", @@@",
       "@@@STEP_LOG_LINE@json.output@        \"package\": \"infra/tools/mac_toolchain/resolved-platform\"@@@",
       "@@@STEP_LOG_LINE@json.output@      }@@@",
       "@@@STEP_LOG_LINE@json.output@    ]@@@",
@@ -122,7 +122,7 @@
       "-kind",
       "mac",
       "-xcode-version",
-      "12b5025f",
+      "10b61",
       "-output-dir",
       "[CACHE]/macos_sdk/XCode.app"
     ],

infra/recipes/gn.expected/cq_mac.json

diff --git a/infra/recipes/gn.expected/cq_mac.json b/infra/recipes/gn.expected/cq_mac.json
index b9ea47c..3ae005b 100644
--- a/infra/recipes/gn.expected/cq_mac.json
+++ b/infra/recipes/gn.expected/cq_mac.json
@@ -122,7 +122,7 @@
       "-root",
       "[CACHE]/macos_sdk",
       "-ensure-file",
-      "infra/tools/mac_toolchain/${platform} git_revision:e9b1fe29fe21a1cd36428c43ea2aba244bd31280",
+      "infra/tools/mac_toolchain/${platform} git_revision:434f5462a77e7103f9d610fa5cabc426bb21502e",
       "-json-output",
       "/path/to/tmp/json"
     ],
@@ -133,7 +133,7 @@
       "@@@STEP_LOG_LINE@json.output@  \"result\": {@@@",
       "@@@STEP_LOG_LINE@json.output@    \"\": [@@@",
       "@@@STEP_LOG_LINE@json.output@      {@@@",
-      "@@@STEP_LOG_LINE@json.output@        \"instance_id\": \"resolved-instance_id-of-git_revision:e9b\", @@@",
+      "@@@STEP_LOG_LINE@json.output@        \"instance_id\": \"resolved-instance_id-of-git_revision:434\", @@@",
       "@@@STEP_LOG_LINE@json.output@        \"package\": \"infra/tools/mac_toolchain/resolved-platform\"@@@",
       "@@@STEP_LOG_LINE@json.output@      }@@@",
       "@@@STEP_LOG_LINE@json.output@    ]@@@",
@@ -149,7 +149,7 @@
       "-kind",
       "mac",
       "-xcode-version",
-      "12b5025f",
+      "10b61",
       "-output-dir",
       "[CACHE]/macos_sdk/XCode.app"
     ],