Move most of runtime/base to libartbase/base

Enforce the layering that code in runtime/base should not depend on
runtime by separating it into libartbase.  Some of the code in
runtime/base depends on the Runtime class, so it cannot be moved yet.
Also, some of the tests depend on CommonRuntimeTest, which itself needs
to be factored (in a subsequent CL).

Bug: 22322814
Test: make -j 50 checkbuild
      make -j 50 test-art-host

Change-Id: I8b096c1e2542f829eb456b4b057c71421b77d7e2
diff --git a/runtime/gc/heap.cc b/runtime/gc/heap.cc
index 19b4acd..3dc2cb5 100644
--- a/runtime/gc/heap.cc
+++ b/runtime/gc/heap.cc
@@ -32,6 +32,7 @@
 #include "base/histogram-inl.h"
 #include "base/logging.h"  // For VLOG.
 #include "base/memory_tool.h"
+#include "base/os.h"
 #include "base/stl_util.h"
 #include "base/systrace.h"
 #include "base/time_utils.h"
@@ -81,7 +82,6 @@
 #include "mirror/reference-inl.h"
 #include "nativehelper/scoped_local_ref.h"
 #include "obj_ptr-inl.h"
-#include "os.h"
 #include "reflection.h"
 #include "runtime.h"
 #include "scoped_thread_state_change-inl.h"