[InstCombine] Add test cases demonstrating creation of extra bswap instrinsic...

[InstCombine] Add test cases demonstrating creation of extra bswap instrinsic calls when when optimizing bswap and bitwise ops when the bswaps have additional uses. NFC

I assume bswap intrinsics are somewhat costly so we should be making sure we are getting rid of them not creating more.

llvm-svn: 307064