[KnownBitsTest] Print name of function when exhaustive tests fail (#89588)

When exhaustive unary/binary tests fail, print the name of the function
being tested as well as the values of the inputs and outputs.

Example of a simulated failure in testing "udiv exact":

    unittests/Support/KnownBitsTest.cpp:99: Failure
Value of: checkResult(Name, Exact, Computed, {Known1, Known2},
CheckOptimality)
Actual: false (udiv exact: Inputs = ???1, ????, Computed = ???1, Exact =
0???)
    Expected: true