Fix GN unittests on windows broken by abs-path change

Mixed up gen_dir and out_dir in one win-only unit test in a recent CL,
https://codereview.chromium.org/1420973003

R=brettw@chromium.org, andybons@chromium.org
BUG=

Review URL: https://codereview.chromium.org/1408793007

Cr-Original-Commit-Position: refs/heads/master@{#356945}
Cr-Mirrored-From: https://chromium.googlesource.com/chromium/src
Cr-Mirrored-Commit: 784ffb68d74d58986d58aaa88e33573608f548ee

tools/gn/function_get_path_info_unittest.cc

diff --git a/tools/gn/function_get_path_info_unittest.cc b/tools/gn/function_get_path_info_unittest.cc
index 5a8c455..e9746a7 100644
--- a/tools/gn/function_get_path_info_unittest.cc
+++ b/tools/gn/function_get_path_info_unittest.cc
@@ -114,6 +114,6 @@
   EXPECT_EQ("//out/Debug/gen/ABS_PATH/foo", Call("/foo/bar.txt", "gen_dir"));
 #if defined(OS_WIN)
   EXPECT_EQ("//out/Debug/gen/ABS_PATH/C/foo",
-            Call("/C:/foo/bar.txt", "out_dir"));
+            Call("/C:/foo/bar.txt", "gen_dir"));
 #endif
 }