Add out-of-line constant pool support to Arm.

src/x64/assembler-x64.h

Index: src/x64/assembler-x64.h
diff --git a/src/x64/assembler-x64.h b/src/x64/assembler-x64.h
index 09d2e7003b324b03207db57bb68c91eb4309e323..5daa2c11ce645d34cdaf4e4f29918e7f8000bcb8 100644
--- a/src/x64/assembler-x64.h
+++ b/src/x64/assembler-x64.h
@@ -1462,6 +1462,12 @@ class Assembler : public AssemblerBase {
   // Use --code-comments to enable.
   void RecordComment(const char* msg, bool force = false);
 
+  // Allocate a constant pool of the correct size for the generated code.
+  MaybeObject* AllocateConstantPool(Heap* heap);
+
+  // Generate the constant pool for the generated code.
+  void PopulateConstantPool(ConstantPoolArray* constant_pool);
+
   // Writes a single word of data in the code stream.
   // Used for inline tables, e.g., jump-tables.
   void db(uint8_t data);