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/oat_file_assistant.h b/runtime/oat_file_assistant.h
index 6da49a9..8d6ec00 100644
--- a/runtime/oat_file_assistant.h
+++ b/runtime/oat_file_assistant.h
@@ -23,12 +23,12 @@
 #include <string>
 
 #include "arch/instruction_set.h"
+#include "base/os.h"
 #include "base/scoped_flock.h"
 #include "base/unix_file/fd_file.h"
 #include "compiler_filter.h"
 #include "class_loader_context.h"
 #include "oat_file.h"
-#include "os.h"
 
 namespace art {