fbits2i/dbits2l failures on macOS

[knn-k]

Tests for fbits2i and dbits2l in compilertriltest/TypeConversionTest.cpp generate the following failures on x86-64 macOS.

https://dev.azure.com/eclipse-omr/omr/_build/results?buildId=2898&view=results

2021-02-05T05:08:53.3978960Z 45: [----------] 38 tests from TypeConversionTest/FloatBitsToInt32
2021-02-05T05:08:53.3979710Z 45: /Users/runner/work/1/s/fvtest/compilertriltest/TypeConversionTest.cpp:1707: Failure
2021-02-05T05:08:53.3980340Z 45:       Expected: exp
2021-02-05T05:08:53.3981190Z 45:       Which is: -4194304
2021-02-05T05:08:53.3981750Z 45: To be equal to: act
2021-02-05T05:08:53.3982270Z 45:       Which is: 2143289344
2021-02-05T05:08:53.3983610Z 45: [  FAILED  ] TypeConversionTest/FloatBitsToInt32.UsingConst/11, where GetParam() = (nan, ("fbits2i", 0x8834ae0)) (1 ms)

2021-02-05T05:08:53.3989090Z 45: [----------] 40 tests from TypeConversionTest/DoubleBitsToInt64
2021-02-05T05:08:53.3989830Z 45: /Users/runner/work/1/s/fvtest/compilertriltest/TypeConversionTest.cpp:1838: Failure
2021-02-05T05:08:53.3990470Z 45:       Expected: exp
2021-02-05T05:08:53.3991340Z 45:       Which is: -2251799813685248
2021-02-05T05:08:53.3991910Z 45: To be equal to: act
2021-02-05T05:08:53.3992640Z 45:       Which is: 9221120237041090560
2021-02-05T05:08:53.3993790Z 45: [  FAILED  ] TypeConversionTest/DoubleBitsToInt64.UsingConst/11, where GetParam() = (nan, ("dbits2l", 0x8837a30)) (1 ms)

[knn-k]

Similar failure on RISC-V Linux, but only with fbits2i: #5810.

[knn-k]

These tests fail also on AArch64 macOS.