Don't invoke goma for linking on mac

Currently, linking with goma causes goma 'local fallback', and goma
allows at most 1 link in parallel (without special flag).

In 520f95147c821e13003362194a5de003a9f5c8f9, linking with goma is
enabled (maybe accidentally). It's better not to use goma for
linking now.

Review-Url: https://codereview.chromium.org/2667383002
Cr-Original-Commit-Position: refs/heads/master@{#447858}
Cr-Mirrored-From: https://chromium.googlesource.com/chromium/src
Cr-Mirrored-Commit: c398506e3abc0799330e39144194d70c00e4032e
1 file changed