[LICM] Make Loop ICM profile aware

Summary:
Hoisting/sinking instruction out of a loop isn't always beneficial. Hoisting an instruction from a cold block inside a loop body out of the loop could hurt performance. This change makes Loop ICM profile aware - it now checks block frequency to make sure hoisting/sinking anly moves instruction to colder block.

Test Plan:

ninja check

Reviewers: asbirlea, sanjoy, reames, nikic, hfinkel, vsk

Reviewed By: asbirlea

Subscribers: fhahn, vsk, davidxl, xbolva00, hiraditya, llvm-commits

Tags: #llvm

Differential Revision: https://reviews.llvm.org/D65060

llvm-svn: 368526