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

[Yingwei Zheng via llvm-commits]

dtcxzyw wrote:

> Maybe there is something else to speed it up?

With debug build:
```
[----------] 12 tests from ConstantFPRangeTest
[ RUN      ] ConstantFPRangeTest.Basics
[       OK ] ConstantFPRangeTest.Basics (0 ms)
[ RUN      ] ConstantFPRangeTest.Equality
[       OK ] ConstantFPRangeTest.Equality (0 ms)
[ RUN      ] ConstantFPRangeTest.SingleElement
[       OK ] ConstantFPRangeTest.SingleElement (0 ms)
[ RUN      ] ConstantFPRangeTest.ExhaustivelyEnumerate
[       OK ] ConstantFPRangeTest.ExhaustivelyEnumerate (70 ms)
[ RUN      ] ConstantFPRangeTest.Enumerate
[       OK ] ConstantFPRangeTest.Enumerate (1 ms)
[ RUN      ] ConstantFPRangeTest.IntersectWith
[       OK ] ConstantFPRangeTest.IntersectWith (0 ms)
[ RUN      ] ConstantFPRangeTest.UnionWith
[       OK ] ConstantFPRangeTest.UnionWith (0 ms)
[ RUN      ] ConstantFPRangeTest.FPClassify
[       OK ] ConstantFPRangeTest.FPClassify (2719 ms)
[ RUN      ] ConstantFPRangeTest.Print
[       OK ] ConstantFPRangeTest.Print (0 ms)
[ RUN      ] ConstantFPRangeTest.NonCanonicalEmptySet
[       OK ] ConstantFPRangeTest.NonCanonicalEmptySet (246 ms)
[ RUN      ] ConstantFPRangeTest.MismatchedSemantics
[       OK ] ConstantFPRangeTest.MismatchedSemantics (1221 ms)
[ RUN      ] ConstantFPRangeTest.makeAllowedFCmpRegion
[       OK ] ConstantFPRangeTest.makeAllowedFCmpRegion (52500 ms)
[----------] 12 tests from ConstantFPRangeTest (56758 ms total)
...
[==========] 783 tests from 109 test suites ran. (107440 ms total)
[  PASSED  ] 783 tests.
```
Please give me one more day to do some profiling.

> The next slowest one is ConstantFPRangeTest.FPClassify at 13s.

Setting `Exhaustive=true` will reduce the test time of `ConstantFPRangeTest.FPClassify` from 2719ms to 61ms.

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