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/mirror/class_ext.cc b/runtime/mirror/class_ext.cc
index c18b219..0819579 100644
--- a/runtime/mirror/class_ext.cc
+++ b/runtime/mirror/class_ext.cc
@@ -19,13 +19,13 @@
 #include "art_method-inl.h"
 #include "base/casts.h"
 #include "base/enums.h"
+#include "base/utils.h"
 #include "class-inl.h"
 #include "dex/dex_file-inl.h"
 #include "gc/accounting/card_table-inl.h"
 #include "object-inl.h"
 #include "object_array.h"
 #include "stack_trace_element.h"
-#include "utils.h"
 #include "well_known_classes.h"
 
 namespace art {