Specific test failures

[tgross35]

Just making a list of failures that should be turned into xfails or fixed.

My loose plan is to put all of these into a single test file and assert that they fail, then if they get fixed they can be converted to test cases.

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i586-unknown-linux-gnu from on https://github.com/rust-lang/libm/pull/379, musl's result is more accurate.

thread 'musl_random_asinhf' panicked at crates/libm-test/tests/compare_built_musl.rs:43:51:
called `Result::unwrap()` on an `Err` value:
    input:    (-0.37330312,) (0xbebf2196,)
    expected: -0.36513534            0xbebaf305
    actual:   -0.36513525            0xbebaf302

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i686-unknown-linux-gnu from on https://github.com/rust-lang/libm/pull/379, musl has the incorrect result here. Not sure why this would be, is compiler-rt incorrect?

 thread 'musl_random_fdim' panicked at crates/libm-test/tests/compare_built_musl.rs:43:51:
called `Result::unwrap()` on an `Err` value: 
    input:    (5.1720626866622296e88, -5.1749184040104636e103) (0x5259ffdf64f0d2f8, 0xd5771addd21280b5)
    expected: 5.174918404010469e103  0x55771addd21280bc
    actual:   5.174918404010468e103  0x55771addd21280bb

Caused by:
    ulp 1 > 0