[FastIsel][AArch64] Fix a think-o in address computation.

When looking through sign/zero-extensions the code would always assume there is
such an extension instruction and use the wrong operand for the address.

There was also a minor issue in the handling of 'AND' instructions. I
accidentially used a 'cast' instead of a 'dyn_cast'.

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@218161 91177308-0d34-0410-b5e6-96231b3b80d8
R600/SI: Un xfail a test that works now

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@218162 91177308-0d34-0410-b5e6-96231b3b80d8
Converting SpillPlacement's BlockFrequency threshold to a ManagedStatic to avoid static constructors and destructors.

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@218163 91177308-0d34-0410-b5e6-96231b3b80d8
R600/SI: Un-xfail tests which work now

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@218164 91177308-0d34-0410-b5e6-96231b3b80d8
R600: Un-xfail a test which passes with pass disabled

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@218165 91177308-0d34-0410-b5e6-96231b3b80d8