[X86] Weaken an overly aggressive assert.

This assert tried to check that AND constants are only on the RHS. But its possible for both operands to be constants if one is opaque which will prevent the AND from being constant folded.

Fixes PR38771

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@341102 91177308-0d34-0410-b5e6-96231b3b80d8
2 files changed