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/monitor_pool.h b/runtime/monitor_pool.h
index 80bae7f..c6b0b0b 100644
--- a/runtime/monitor_pool.h
+++ b/runtime/monitor_pool.h
@@ -22,7 +22,7 @@
 #include "base/allocator.h"
 #ifdef __LP64__
 #include <stdint.h>
-#include "atomic.h"
+#include "base/atomic.h"
 #include "runtime.h"
 #else
 #include "base/stl_util.h"     // STLDeleteElements