[X86] Rename __builtin_ia32_pslldqi128 to __builtin_ia32_pslldqi128_byteshift...

[X86] Rename __builtin_ia32_pslldqi128 to __builtin_ia32_pslldqi128_byteshift and similar for other sizes. Remove the multiply by 8 from the header files.

The previous names took the shift amount in bits to match gcc and required a multiply by 8 in the header. This creates a misleading error message when we check the range of the immediate to the builtin since the allowed range also got multiplied by 8.

This commit changes the builtins to use a byte shift amount to match the underlying instruction and the Intel intrinsic.

Fixes the remaining issue from PR37795.

llvm-svn: 334773