ICData::NumberOfChecks is O(n) so don't call it in loops

runtime/vm/intermediate_language_x64.cc

 // Copyright (c) 2013, the Dart project authors.  Please see the AUTHORS file
 // for details. All rights reserved. Use of this source code is governed by a
 // BSD-style license that can be found in the LICENSE file.
 
 #include "vm/globals.h"  // Needed here to get TARGET_ARCH_X64.
 #if defined(TARGET_ARCH_X64)
 
 #include "vm/intermediate_language.h"
 
 #include "vm/compiler.h"
@@ skipping 5270 matching lines @@
   Label do_call, done;
   // Check for overflow and that it fits into Smi.
   __ movq(temp, result);
   __ shlq(temp, Immediate(1));
   __ j(OVERFLOW, &do_call, Assembler::kNearJump);
   __ SmiTag(result);
   __ jmp(&done);
   __ Bind(&do_call);
   ASSERT(instance_call()->HasICData());
   const ICData& ic_data = *instance_call()->ic_data();
-  ASSERT((ic_data.NumberOfChecks() == 1));
+  ASSERT(ic_data.NumberOfChecksIs(1));
   const Function& target = Function::ZoneHandle(ic_data.GetTargetAt(0));
 
   const intptr_t kNumberOfArguments = 1;
   __ pushq(value_obj);
   compiler->GenerateStaticCall(deopt_id(), instance_call()->token_pos(), target,
                                kNumberOfArguments,
                                Object::null_array(),  // No argument names.
                                locs(), ICData::Handle());
   __ Bind(&done);
 }
@@ skipping 1448 matching lines @@
   __ Drop(1);
   __ popq(result);
 }
 
 
 }  // namespace dart
 
 #undef __
 
 #endif  // defined TARGET_ARCH_X64