Refactor FrameAndConstantPoolScope and ConstantPoolUnavailableScope to be architecture independent

src/x87/assembler-x87.h

Index: src/x87/assembler-x87.h
diff --git a/src/x87/assembler-x87.h b/src/x87/assembler-x87.h
index d37c9d77dcb59cda879f4bd696675b293881c9c2..c864c1abe8f0c2b2a9e303c01cf2877139249955 100644
--- a/src/x87/assembler-x87.h
+++ b/src/x87/assembler-x87.h
@@ -963,9 +963,16 @@ class Assembler : public AssemblerBase {
   // Generate the constant pool for the generated code.
   void PopulateConstantPool(ConstantPoolArray* constant_pool);
 
+  bool is_constant_pool_available() const { return false; }
+
  protected:
   byte* addr_at(int pos) { return buffer_ + pos; }
 
+  void set_constant_pool_available(bool available) {
+    // Constant pool is not supported on x87.
+    UNREACHABLE();
+  }
+
 
  private:
   uint32_t long_at(int pos)  {
@@ -1025,6 +1032,10 @@ class Assembler : public AssemblerBase {
 
   PositionsRecorder positions_recorder_;
   friend class PositionsRecorder;
+
+  // constant pool
+  friend class FrameAndConstantPoolScope;
+  friend class ConstantPoolUnavailableScope;
 };