[AMDGPU] Combine and x, (sext cc from i1) => select cc, x, 0

[AMDGPU] Combine and x, (sext cc from i1) => select cc, x, 0

Also factored out function to check if a boolean is an already
deserialized value which does not require v_cndmask_b32 to be
loaded. Added binary logical operators to its check.

Differential Revision: https://reviews.llvm.org/D34500

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@306439 91177308-0d34-0410-b5e6-96231b3b80d8