Upstream iOS recipe infrastructure find Xcode script
Upstream iOS recipe infrastructure find Xcode script

This upstreams the script which finds and attempts to switch to a specific Xcode version, required for our recipe infrastructure.

This depends on https://codereview.chromium.org/880593004.

BUG=452193

Review URL: https://codereview.chromium.org/867843004

git-svn-id: 239fca9b83025a0b6f823aeeca02ba5be3d9fd76@293869 0039d316-1c4b-4281-b951-d872f2087c98

eunchong/build,eunchong/build,eunchong/build,eunchong/build