[Hexagon] Adding allocframe, post-increment circular immediate stores, post-increment...

[Hexagon] Adding allocframe, post-increment circular immediate stores, post-increment circular register stores, and bit reversed post-increment stores.

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@224957 91177308-0d34-0410-b5e6-96231b3b80d8