[llvm] [test] Disable makeAllowedFCmpRegion due to taking too long (PR #111056)

[via llvm-commits]

vporpo wrote:

> I don't have enough space to test the debug build. 

I tried it and it takes 64 seconds in Debug. The next slowest one is `ConstantFPRangeTest.FPClassify` at 13s.

https://github.com/llvm/llvm-project/pull/111056