On Windows build, making the /bigobj flag global , instead of passing it per file.

To avoid having this flag be passed in per/file manner, we are instead
passing it globally.

This fixes this bug: https://bugs.llvm.org/show_bug.cgi?id=46733

Reviewed-by: aaron.ballman, beanz, meinersbur

Differential Revision: https://reviews.llvm.org/D84038