[X86] Add test case that shows a scalar sqrtsd intrinsic of a 128-bit vector load...

[X86] Add test case that shows a scalar sqrtsd intrinsic of a 128-bit vector load using the load form of the sqrtsd instruction which violates the intrinsic semantics.

The sqrtsd instruction only loads 64-bits and writes bits 63:0 with the sqrt result. Bits 127:64 are preserved in the destination register. The semantics of the intrinsic indicate bits 127:64 should come from the intrinsic argument which in this case is a 128-bit load. So the generated code should have a 128-bit load and use a register form of sqrtsd.

llvm-svn: 288780