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

src/a64/assembler-a64.h

Index: src/a64/assembler-a64.h
diff --git a/src/a64/assembler-a64.h b/src/a64/assembler-a64.h
index ca38e066d9b1e71198e642616d0c1748d133154e..684d6f94d8670500844628e417a2ac4263297b24 100644
--- a/src/a64/assembler-a64.h
+++ b/src/a64/assembler-a64.h
@@ -1725,6 +1725,9 @@ class Assembler : public AssemblerBase {
   // Check if is time to emit a constant pool.
   void CheckConstPool(bool force_emit, bool require_jump);
 
+  // Generate the constant pool for the generated code.
+  void PopulateConstantPool(ConstantPoolArray* constant_pool);
+
   // Available for constrained code generation scopes. Prefer
   // MacroAssembler::Mov() when possible.
   inline void LoadRelocated(const CPURegister& rt, const Operand& operand);