Emit StackMap section on AArch64 target

[• ossy]

Summary

http://reviews.llvm.org/D4574 added StackMap support and emit StackMap section on X86 target.
We need to emit this section on AArch64 too for FTL JIT of WebKit.

[ributzka]

LGTM

[dblaikie]

Test coverage?

[Eugene.Zelenko]

Obsoleted by rL234315.

lib/Target/AArch64/AArch64AsmPrinter.cpp

       }
       Stubs.clear();
     }
+    SM.serializeToStackMapSection();
   }
 
 }