[GlobalISel][AArch64] Add back constant select tests. NFC.
[GlobalISel][AArch64] Add back constant select tests. NFC.

More of r297856.

git-svn-id: 0ff597fd157e6f4fc38580e8d64ab130330d2411@297859 91177308-0d34-0410-b5e6-96231b3b80d8
(cherry picked from commit 8aaf47200a5a6e1a7e83d019ee1e20320f9f9407)

apple/swift-llvm,apple/swift-llvm,apple/swift-llvm,apple/swift-llvm,apple/swift-llvm,apple/swift-llvm,apple/swift-llvm,apple/swift-llvm