add more -O0 builds

x86 -O0 codegen has come up as an issue in
https://bugs.chromium.org/p/chromium/issues/detail?id=974542,
and it'd be good to keep on top of how GCC and Clang both do,
for both 32-bit and 64-bit x86.

Bug: chromium:974542
Change-Id: I8bd212e240f72a305bda26d05912058c15d42ad9
Reviewed-on: https://skia-review.googlesource.com/c/skcms/+/221319
Auto-Submit: Mike Klein <mtklein@google.com>
Commit-Queue: Brian Osman <brianosman@google.com>
Reviewed-by: Brian Osman <brianosman@google.com>
4 files changed