Check the local frame alignment for determining whether dynamic stack

Check the local frame alignment for determining whether dynamic stack
alignment should be performed. Otherwise dynamic realignment may trigger
when the register allocator has already used the frame pointer as a general
purpose register. That is, we need to make sure that the list of reserved
registers doesn't change after register allocation.

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@112986 91177308-0d34-0410-b5e6-96231b3b80d8