[compiler-rt] [test] [builtins] Remove obsolete/UB tests in __fixuns?fdi based

[mgorny]

Summary

Remove the failing tests for fixunssfdi() and fixunsdfdi() that
relied on undefined (and most likely obsolete in terms of compiler-rt
implementation behavior).

Both tests presumed that 0x1.p+64 would be converted to
0xFFFFFFFFFFFFFFFFLL, that is the largest value in uint64 range.
However, the C/C++ standards do not specify the behavior for converting
a floating-point value to an integer of smaller range, and in this case
both libgcc and compiler-rt implementations return 0 instead.

Since the current behavior is correct with regards to standards
and there is no good way of expressing 0xFFFFFFFFFFFFFFFFLL in single-
or double-precision float, I've removed the failing test altogether.

[dschuff]

I don't have any particular ownership or knowledge of this file, but the change still LGTM

test/builtins/Unit/fixunsdfdi_test.c

if (test__fixunsdfdi(0x1.FFFFFFFFFFFFFp+63, 0xFFFFFFFFFFFFF800LL))
         return 1;
     if (test__fixunsdfdi(0x1.0000000000000p+63, 0x8000000000000000LL))
         return 1;
     if (test__fixunsdfdi(0x1.FFFFFFFFFFFFFp+62, 0x7FFFFFFFFFFFFC00LL))
         return 1;
     if (test__fixunsdfdi(0x1.FFFFFFFFFFFFEp+62, 0x7FFFFFFFFFFFF800LL))
         return 1;
 
-    if (test__fixunsdfdi(0x1.p+64, 0xFFFFFFFFFFFFFFFFLL))
-        return 1;
-
 #if !TARGET_LIBGCC
     if (test__fixunsdfdi(-0x1.FFFFFFFFFFFFFp+62, 0))
         return 1;
     if (test__fixunsdfdi(-0x1.FFFFFFFFFFFFEp+62, 0))
         return 1;
 #endif
 
    return 0;
 }

test/builtins/Unit/fixunssfdi_test.c

#if !TARGET_LIBGCC
     if (test__fixunssfdi(-2.01F, 0))
         return 1;
 #endif
 
     if (test__fixunssfdi(0x1.FFFFFEp+63F, 0xFFFFFF0000000000LL))
         return 1;
     if (test__fixunssfdi(0x1.000000p+63F, 0x8000000000000000LL))
         return 1;
-    if (test__fixunssfdi(0x1.000000p+64F, 0xFFFFFFFFFFFFFFFFLL))
-        return 1;
     if (test__fixunssfdi(0x1.FFFFFEp+62F, 0x7FFFFF8000000000LL))
         return 1;
     if (test__fixunssfdi(0x1.FFFFFCp+62F, 0x7FFFFF0000000000LL))
         return 1;
 
 #if !TARGET_LIBGCC
     if (test__fixunssfdi(-0x1.FFFFFEp+62F, 0x0000000000000000LL))
         return 1;
     if (test__fixunssfdi(-0x1.FFFFFCp+62F, 0x0000000000000000LL))
         return 1;
 #endif
 
    return 0;
 }