[InstCombine] Remove a couple of asserts based on incorrect assumptions

Summary:
These asserts are based on the assumption that the order of true/false operands in a select and those in the compare would always be the same.
This fixes PR39595.

Reviewers: craig.topper, spatel, dmgreen

Reviewed By: craig.topper

Subscribers: llvm-commits

Differential Revision: https://reviews.llvm.org/D54359

llvm-svn: 346874