workaround: use an absolute path to run XCTRun.

If we rebase the path, gn seems to confuse to set paths from current
working directory to have chrome/ios directory.
However, it should not have that.
Since XCRun path won't be sent to Goma, we do not need to normalize
that here.

Bug: 1015730
Change-Id: If175706ae564cbf124c53f0e0e1255b439cea682
Reviewed-on: https://chromium-review.googlesource.com/c/chromium/src/+/2022046
Commit-Queue: Sylvain Defresne <sdefresne@chromium.org>
Auto-Submit: Yoshisato Yanagisawa <yyanagisawa@chromium.org>
Reviewed-by: Sylvain Defresne <sdefresne@chromium.org>
Cr-Commit-Position: refs/heads/master@{#735812}

build/config/ios/ios_sdk.gni

@@ -110,6 +110,7 @@ if (ios_sdk_path == "") {
   }
   script_name = "//build/config/mac/sdk_info.py"
   _ios_sdk_result = exec_script(script_name, ios_sdk_info_args, "scope")
+  ios_sdk_platform_abs_path = _ios_sdk_result.sdk_platform_path
   if (ios_enable_relative_sdk_path) {
     ios_sdk_path = rebase_path(_ios_sdk_result.sdk_path, root_build_dir)
     ios_sdk_platform_path =

build/config/ios/rules.gni

@@ -1873,7 +1873,7 @@ template("ios_xcuitest_test_runner_bundle") {
   }
 
   _xctrunner_path =
-      "$ios_sdk_platform_path/Developer/Library/Xcode/Agents/XCTRunner.app"
+      "$ios_sdk_platform_abs_path/Developer/Library/Xcode/Agents/XCTRunner.app"
 
   _info_plist_merge_plist = _target_name + "_info_plist_merge_plist"
   _info_plist_target = _target_name + "_info_plist"