Remove default monomorphic check code from functions and stubs that do not need it.

runtime/vm/assembler_arm.h

Index: runtime/vm/assembler_arm.h
diff --git a/runtime/vm/assembler_arm.h b/runtime/vm/assembler_arm.h
index 4c172275f8cc9622e9e5af4d1779dcd6c7803ef8..0b91ba1529b2defdc859eabae64042e24a37b3b9 100644
--- a/runtime/vm/assembler_arm.h
+++ b/runtime/vm/assembler_arm.h
@@ -366,10 +366,10 @@ class Assembler : public ValueObject {
   explicit Assembler(bool use_far_branches = false)
       : buffer_(),
         prologue_offset_(-1),
+        has_single_entry_point_(true),
         use_far_branches_(use_far_branches),
         comments_(),
         constant_pool_allowed_(false) {
-    MonomorphicCheckedEntry();
   }
 
   ~Assembler() { }
@@ -382,6 +382,7 @@ class Assembler : public ValueObject {
   // Misc. functionality
   intptr_t CodeSize() const { return buffer_.Size(); }
   intptr_t prologue_offset() const { return prologue_offset_; }
+  bool has_single_entry_point() const { return has_single_entry_point_; }
 
   // Count the fixups that produce a pointer offset, without processing
   // the fixups.  On ARM there are no pointers in code.
@@ -946,7 +947,6 @@ class Assembler : public ValueObject {
   void EnterStubFrame();
   void LeaveStubFrame();
 
-  void NoMonomorphicCheckedEntry();
   void MonomorphicCheckedEntry();
 
   // The register into which the allocation stats table is loaded with
@@ -1019,9 +1019,8 @@ class Assembler : public ValueObject {
  private:
   AssemblerBuffer buffer_;  // Contains position independent code.
   ObjectPoolWrapper object_pool_wrapper_;
-
   int32_t prologue_offset_;
-
+  bool has_single_entry_point_;
   bool use_far_branches_;
 
   // If you are thinking of using one or both of these instructions directly,