Fix issues with Arm's use of embedded constant pools

src/x64/assembler-x64.cc

Index: src/x64/assembler-x64.cc
diff --git a/src/x64/assembler-x64.cc b/src/x64/assembler-x64.cc
index cb93ab878b9517a1348d32df1914fa9cff856f65..ae081e14bb90955174963994cc1124a4a2e6aa0c 100644
--- a/src/x64/assembler-x64.cc
+++ b/src/x64/assembler-x64.cc
@@ -316,6 +316,14 @@ void Assembler::Align(int m) {
 }
 
 
+void Assembler::DataAlign(int m) {
+  DCHECK(m >= 2 && base::bits::IsPowerOfTwo32(m));
+  while ((pc_offset() & (m - 1)) != 0) {
+    db(0);
+  }
+}
+
+
 void Assembler::CodeTargetAlign() {
   Align(16);  // Preferred alignment of jump targets on x64.
 }