Remove the --collect-maps flag. Maps should be always collected.

test/cctest/test-heap.cc

 // Copyright 2012 the V8 project authors. All rights reserved.
 // Redistribution and use in source and binary forms, with or without
 // modification, are permitted provided that the following conditions are
 // met:
 //
 //     * Redistributions of source code must retain the above copyright
 //       notice, this list of conditions and the following disclaimer.
 //     * Redistributions in binary form must reproduce the above
 //       copyright notice, this list of conditions and the following
 //       disclaimer in the documentation and/or other materials provided
@@ skipping 3389 matching lines @@
   // Count number of live transitions after marking.  Note that one transition
   // is left, because 'o' still holds an instance of one transition target.
   int transitions_after = CountMapTransitions(
       Map::cast(root->map()->GetBackPointer()));
   CHECK_EQ(1, transitions_after);
 }
 #endif  // DEBUG
 
 
 TEST(Regress2143a) {
-  i::FLAG_collect_maps = true;
   i::FLAG_incremental_marking = true;
   CcTest::InitializeVM();
   v8::HandleScope scope(CcTest::isolate());
 
   // Prepare a map transition from the root object together with a yet
   // untransitioned root object.
   CompileRun("var root = new Object;"
              "root.foo = 0;"
              "root = new Object;");
 
@@ skipping 19 matching lines @@
           *v8::Handle<v8::Object>::Cast(
               CcTest::global()->Get(v8_str("root"))));
 
   // The root object should be in a sane state.
   CHECK(root->IsJSObject());
   CHECK(root->map()->IsMap());
 }
 
 
 TEST(Regress2143b) {
-  i::FLAG_collect_maps = true;
   i::FLAG_incremental_marking = true;
   i::FLAG_allow_natives_syntax = true;
   CcTest::InitializeVM();
   v8::HandleScope scope(CcTest::isolate());
 
   // Prepare a map transition from the root object together with a yet
   // untransitioned root object.
   CompileRun("var root = new Object;"
              "root.foo = 0;"
              "root = new Object;");
@@ skipping 2502 matching lines @@
   size_t counter2 = 2000;
   tracer->SampleAllocation(time2, counter2, counter2);
   size_t throughput = tracer->AllocationThroughputInBytesPerMillisecond(100);
   CHECK_EQ(2 * (counter2 - counter1) / (time2 - time1), throughput);
   int time3 = 1000;
   size_t counter3 = 30000;
   tracer->SampleAllocation(time3, counter3, counter3);
   throughput = tracer->AllocationThroughputInBytesPerMillisecond(100);
   CHECK_EQ(2 * (counter3 - counter1) / (time3 - time1), throughput);
 }