Merge remote-tracking branch 'aosp/upstream-master' into update-shaderc

Includes:
0610978 Add new Intel token reservations.
77240d9 Add new tokens for SPV_AMD_shader_fragment_mask, and rebuild all headers.
b94aced Add new tokens for SPV_AMD_shader_fragment_mask

Test: checkbuild.py on Linux; unit tests on Windows
Change-Id: I9cc8b875f6278d14de264cc733307b2500cb2ab5