Always set alwaysOutOfDate for PBXShellScriptBuildPhase.

This unchecks the:
 'Run script: [x] Based on dependency analysis'
 'Will force script to run in all incremental builds.'
box in Xcode.

Change-Id: Ia88827da7e519a48420670c17ac22c75afc26210
Reviewed-on: https://gn-review.googlesource.com/c/gn/+/14100
Reviewed-by: Sylvain Defresne <sdefresne@chromium.org>
Commit-Queue: Sylvain Defresne <sdefresne@chromium.org>

src/gn/xcode_object.cc

diff --git a/src/gn/xcode_object.cc b/src/gn/xcode_object.cc
index c9b69a3..4f2b66b 100644
--- a/src/gn/xcode_object.cc
+++ b/src/gn/xcode_object.cc
@@ -968,6 +968,7 @@
   const IndentRules rules = {false, indent + 1};
   out << indent_str << Reference() << " = {\n";
   PrintProperty(out, rules, "isa", ToString(Class()));
+  PrintProperty(out, rules, "alwaysOutOfDate", 1u);
   PrintProperty(out, rules, "buildActionMask", 0x7fffffffu);
   PrintProperty(out, rules, "files", files_);
   PrintProperty(out, rules, "inputPaths", EmptyPBXObjectVector());