Refactoring of snapshots. This simplifies and improves

test/cctest/test-heap.cc

Index: test/cctest/test-heap.cc
===================================================================
--- test/cctest/test-heap.cc	(revision 12439)
+++ test/cctest/test-heap.cc	(working copy)
@@ -1244,7 +1244,9 @@
   for (HeapObject* obj = iterator.next();
        obj != NULL;
        obj = iterator.next()) {
-    size_of_objects_2 += obj->Size();
+    if (!obj->IsFreeSpace()) {
+      size_of_objects_2 += obj->Size();
+    }
   }
   // Delta must be within 5% of the larger result.
   // TODO(gc): Tighten this up by distinguishing between byte
@@ -1273,7 +1275,6 @@
   // that the scavenger does not undo the filling.
   v8::HandleScope scope;
   AlwaysAllocateScope always_allocate;
-  LinearAllocationScope allocate_linearly;
   intptr_t available = new_space->EffectiveCapacity() - new_space->Size();
   intptr_t number_of_fillers = (available / FixedArray::SizeFor(32)) - 1;
   for (intptr_t i = 0; i < number_of_fillers; i++) {
@@ -1928,8 +1929,13 @@
   HEAP->CollectAllGarbage(Heap::kNoGCFlags, "triggered by test 2");
   CHECK_GE(number_of_test_pages + 1, old_pointer_space->CountTotalPages() * 2);
 
-  // Triggering a last-resort GC should cause all pages to be released
-  // to the OS so that other processes can seize the memory.
+  // Triggering a last-resort GC should cause all pages to be released to the
+  // OS so that other processes can seize the memory.  If we get a failure here
+  // where there are 2 pages left instead of 1, then we should increase the
+  // size of the first page a little in SizeOfFirstPage in spaces.cc.  The
+  // first page should be small in order to reduce memory used when the VM
+  // boots, but if the 20 small arrays don't fit on the first page then that's
+  // an indication that it is too small.
   HEAP->CollectAllAvailableGarbage("triggered really hard");
   CHECK_EQ(1, old_pointer_space->CountTotalPages());
 }