[X86SchedSandyBridge] update cost of COPY to 1 cycle from 0

To match the cost of other scheduling models. This is expected to
schedule mov instructions around INLINEASM less frequently for the
default machineschedule (pre-RA scheduling).

Suggested by Craig Topper.

Link: https://github.com/llvm/llvm-project/issues/41914

Reviewed By: RKSimon

Differential Revision: https://reviews.llvm.org/D122350