[llvm] workflows/release-binaries: Disable Flang on x86_64 macOS (PR #127216)

[Tom Stellard via llvm-commits]

tstellar wrote:

> LGTM.
> 
> I'm wondering if compiling just uses too much RAM and it goes to swap?

It could be, the large X86_64  mac runners have a low RAM/CPU ratio: 30/12.  The Linux runners are 64/16 and it builds fine there.  Maybe I need to try to get this working again: https://github.com/llvm/llvm-project/pull/95672

https://github.com/llvm/llvm-project/pull/127216