Refactor immune region logic into its own file.

Added immune_region.cc/.h in the collector directory. Changed the
functionality to no longer assume spaces are added to immune region
in ascending order.

Change-Id: Id1d643b3849ad2695e8a151dbbb74a5035644472
diff --git a/runtime/gc/space/space-inl.h b/runtime/gc/space/space-inl.h
index 02a63f6..3a715ab 100644
--- a/runtime/gc/space/space-inl.h
+++ b/runtime/gc/space/space-inl.h
@@ -21,6 +21,7 @@
 
 #include "dlmalloc_space.h"
 #include "image_space.h"
+#include "large_object_space.h"
 
 namespace art {
 namespace gc {