[llvm][NFC] Rename CallAnalyzer::onCommonInstructionSimplification

Summary:
It is called when instructions aren't simplified, and the implementation
is expected to account for a penalty. Renamed to
onCommonInstructionMissedSimplification.

Reviewers: davidxl, eraman

Reviewed By: davidxl

Subscribers: hiraditya, baloghadamsoftware, haicheng, a.sidorin, Szelethus, donat.nagy, dkrupp, llvm-commits

Tags: #llvm

Differential Revision: https://reviews.llvm.org/D73662