[AArch64] Print instruction before atomic semantic annotations

[AArch64] Print instruction before atomic semantic annotations

Commit r353303 added annotations when acquire semantics
were dropped from an instruction.

printAnnotation was called before printInstruction.
So if you didn't set a separate comment output stream
you got <comment><instr> instead of <instr><comment>
as expected.

To fix this move the new printAnnotation to after
the instruction is printed.

Differential Revision: https://reviews.llvm.org/D58059

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@354565 91177308-0d34-0410-b5e6-96231b3b80d8