Update this a bit more to represent how the prologue should work:

Update this a bit more to represent how the prologue should work:

a) frame setup instructions define the prologue
b) we shouldn't change our location mid-stream

Add a test to make sure that the stack adjustment stays within
the prologue.

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@165250 91177308-0d34-0410-b5e6-96231b3b80d8