[X86] Remove wrong ReadAdvance from multiclass sse_fp_unop_s.

A ReadAdvance was incorrectly added to the SchedReadWrite list associated with
the following SSE instructions:

sqrtss
sqrtsd
rsqrtss
rcpss

As a consequence, a wrong operand latency was computed for the register operand
used as the base address of the folded load operand.

This patch removes the wrong ReadAdvance, and updates the llvm-mca test cases.
There is still a problem with correctly modeling partial register writes on XMM
registers This other problem is currently tracked here:
https://bugs.llvm.org/show_bug.cgi?id=38813

Differential Revision: https://reviews.llvm.org/D51542

llvm-svn: 341326