Move ArrayRef to runtime/base

Will be used in upcoming CLs regarding VDEX and VerifierDeps.

Test: m test-art-host
Change-Id: I68e611a4a52246c2bdf45eab7c61f3212908afd4
diff --git a/compiler/oat_writer.h b/compiler/oat_writer.h
index 77525f1..dd7d699 100644
--- a/compiler/oat_writer.h
+++ b/compiler/oat_writer.h
@@ -21,6 +21,7 @@
 #include <cstddef>
 #include <memory>
 
+#include "base/array_ref.h"
 #include "base/dchecked_vector.h"
 #include "linker/relative_patcher.h"  // For linker::RelativePatcherTargetProvider.
 #include "mem_map.h"
@@ -29,7 +30,6 @@
 #include "oat.h"
 #include "os.h"
 #include "safe_map.h"
-#include "utils/array_ref.h"
 
 namespace art {