[PGO][PGSO] Update BFI in CodeGenPrepare::optimizeSelectInst.

Summary:
Without the BFI update, some hot blocks are incorrectly treated as cold code.

This fixes a FDO perf regression in the TSVC benchmark from D71288.

Reviewers: davidxl

Subscribers: hiraditya, llvm-commits

Tags: #llvm

Differential Revision: https://reviews.llvm.org/D73146