Reland of "[heap] Parallel newspace evacuation, semispace copy, and compaction \o/"

test/cctest/heap/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 3496 matching lines @@
   CHECK(root->map()->IsMap());
 }
 
 
 TEST(ReleaseOverReservedPages) {
   if (FLAG_never_compact) return;
   i::FLAG_trace_gc = true;
   // The optimizer can allocate stuff, messing up the test.
   i::FLAG_crankshaft = false;
   i::FLAG_always_opt = false;
+  // Parallel compaction increases fragmentation, depending on how existing
+  // memory is distributed. Since this is non-deterministic because of
+  // concurrent sweeping, we disable it for this test.
+  i::FLAG_parallel_compaction = false;
+  // Concurrent sweeping adds non determinism, depending on when memory is
+  // available for further reuse.
+  i::FLAG_concurrent_sweeping = false;
   CcTest::InitializeVM();
   Isolate* isolate = CcTest::i_isolate();
   Factory* factory = isolate->factory();
   Heap* heap = isolate->heap();
   v8::HandleScope scope(CcTest::isolate());
   static const int number_of_test_pages = 20;
 
   // Prepare many pages with low live-bytes count.
   PagedSpace* old_space = heap->old_space();
   CHECK_EQ(1, old_space->CountTotalPages());
@@ skipping 2913 matching lines @@
   isolate->IncrementJsCallsFromApiCounter();
   isolate->IncrementJsCallsFromApiCounter();
   isolate->IncrementJsCallsFromApiCounter();
   calls_per_ms = memory_reducer->SampleAndGetJsCallsPerMs(4);
   CheckDoubleEquals(2, calls_per_ms);
 }
 
 
 }  // namespace internal
 }  // namespace v8