Rename current register allocator implementation

This will allow a cleaner commit in an upcoming
refactoring of register allocation.

Test: m test-art-host

Change-Id: If420c97b088b3c934411ff83373e024003120746
diff --git a/compiler/optimizing/graph_visualizer.cc b/compiler/optimizing/graph_visualizer.cc
index e14f603..0b4c569 100644
--- a/compiler/optimizing/graph_visualizer.cc
+++ b/compiler/optimizing/graph_visualizer.cc
@@ -31,7 +31,7 @@
 #include "nodes.h"
 #include "optimization.h"
 #include "reference_type_propagation.h"
-#include "register_allocator.h"
+#include "register_allocator_linear_scan.h"
 #include "ssa_liveness_analysis.h"
 #include "utils/assembler.h"