X86 intrinsics: cmpge|gt|nge|ngt_ss|_sd

These intrinsics should return the comparision result in the low bits and keep
the high bits of the first source operand.

When calling to builtin functions, the source operands are swapped and the high
bits of the second source operand are kept. To fix the issue, an extra
shufflevector is used.

rdar://14153896