Drop IsPregenerated() and allow_stub_calls flag.

src/x64/macro-assembler-x64.h

Index: src/x64/macro-assembler-x64.h
diff --git a/src/x64/macro-assembler-x64.h b/src/x64/macro-assembler-x64.h
index 06b2f801a3ed22030b4ca48101da2249aa76d750..f1a359a0b3144c624da9344edc05388670bf59fc 100644
--- a/src/x64/macro-assembler-x64.h
+++ b/src/x64/macro-assembler-x64.h
@@ -1393,8 +1393,6 @@ class MacroAssembler: public Assembler {
   // Verify restrictions about code generated in stubs.
   void set_generating_stub(bool value) { generating_stub_ = value; }
   bool generating_stub() { return generating_stub_; }
-  void set_allow_stub_calls(bool value) { allow_stub_calls_ = value; }
-  bool allow_stub_calls() { return allow_stub_calls_; }
   void set_has_frame(bool value) { has_frame_ = value; }
   bool has_frame() { return has_frame_; }
   inline bool AllowThisStubCall(CodeStub* stub);
@@ -1444,7 +1442,6 @@ class MacroAssembler: public Assembler {
   static const int kSmiShift = kSmiTagSize + kSmiShiftSize;
 
   bool generating_stub_;
-  bool allow_stub_calls_;
   bool has_frame_;
   bool root_array_available_;