Separate file utilities from utils.cc

Reduce the dependencies from utils.cc to arch/ subdirectories, etc.

Bug: 22322814
Test: make test-art-host
Change-Id: I4decd15ff4ec460735bfb58cebb1c6a1bf32b68f
diff --git a/runtime/signal_catcher.cc b/runtime/signal_catcher.cc
index a1f14be..bf5d718 100644
--- a/runtime/signal_catcher.cc
+++ b/runtime/signal_catcher.cc
@@ -34,6 +34,7 @@
 #endif
 
 #include "arch/instruction_set.h"
+#include "base/file_utils.h"
 #include "base/time_utils.h"
 #include "base/unix_file/fd_file.h"
 #include "class_linker.h"