Fix issues with Arm's use of embedded constant pools

src/arm64/assembler-arm64.h

Index: src/arm64/assembler-arm64.h
diff --git a/src/arm64/assembler-arm64.h b/src/arm64/assembler-arm64.h
index 7346648a9b02aed4e8150d7359f7c8c5ce898be7..5fab081d4b41b52ca802c99d3cbf6cb3349048c0 100644
--- a/src/arm64/assembler-arm64.h
+++ b/src/arm64/assembler-arm64.h
@@ -851,6 +851,9 @@ class Assembler : public AssemblerBase {
   // possible to align the pc offset to a multiple
   // of m. m must be a power of 2 (>= 4).
   void Align(int m);
+  // Insert the smallest number of zero bytes possible to align the pc offset
+  // to a mulitple of m. m must be a power of 2 (>= 2).
+  void DataAlign(int m);
 
   inline void Unreachable();