Use standard datastructures for tracking constant pool entries.

src/arm/macro-assembler-arm.cc

Index: src/arm/macro-assembler-arm.cc
diff --git a/src/arm/macro-assembler-arm.cc b/src/arm/macro-assembler-arm.cc
index 018880d51f5f8b52ac018ebc2b9c136c3eb08d14..2c06e1ea74ae0472f93b2b76f2fbee1745bf5593 100644
--- a/src/arm/macro-assembler-arm.cc
+++ b/src/arm/macro-assembler-arm.cc
@@ -3992,8 +3992,8 @@ CodePatcher::~CodePatcher() {
   }
 
   // Check that we don't have any pending constant pools.
-  DCHECK(masm_.num_pending_32_bit_constants_ == 0);
-  DCHECK(masm_.num_pending_64_bit_constants_ == 0);
+  DCHECK(masm_.pending_32_bit_constants_.empty());
+  DCHECK(masm_.pending_64_bit_constants_.empty());
 
   // Check that the code was patched as expected.
   DCHECK(masm_.pc_ == address_ + size_);