Fix main space memory leak and add checks.

The hypothesis is that we were leaking the main space and its
bitmaps, then eventually we would run out of virtual address space,
which would cause a null bitmap (DCHECK). Finally when we tried
adding the space with a null bitmap to the heap bitmap it segfaulted.

Changed some non performance critical DCHECK -> CHECK.

Bug: 16563323
Change-Id: I08a1f873752e28ebcf63ebbd90f92d994d7ca96b
diff --git a/runtime/gc/space/malloc_space.cc b/runtime/gc/space/malloc_space.cc
index 27f92b5..ba7e5c1 100644
--- a/runtime/gc/space/malloc_space.cc
+++ b/runtime/gc/space/malloc_space.cc
@@ -51,12 +51,12 @@
     live_bitmap_.reset(accounting::ContinuousSpaceBitmap::Create(
         StringPrintf("allocspace %s live-bitmap %d", name.c_str(), static_cast<int>(bitmap_index)),
         Begin(), NonGrowthLimitCapacity()));
-    DCHECK(live_bitmap_.get() != nullptr) << "could not create allocspace live bitmap #"
+    CHECK(live_bitmap_.get() != nullptr) << "could not create allocspace live bitmap #"
         << bitmap_index;
     mark_bitmap_.reset(accounting::ContinuousSpaceBitmap::Create(
         StringPrintf("allocspace %s mark-bitmap %d", name.c_str(), static_cast<int>(bitmap_index)),
         Begin(), NonGrowthLimitCapacity()));
-    DCHECK(live_bitmap_.get() != nullptr) << "could not create allocspace mark bitmap #"
+    CHECK(live_bitmap_.get() != nullptr) << "could not create allocspace mark bitmap #"
         << bitmap_index;
   }
   for (auto& freed : recent_freed_objects_) {