ART: Don't nest indenters in oatdump.

Reduces the time taken by the oatdump_test by ~12s (15%)
on host and ~55s (9%) on N5.

Change-Id: I99bb16ff5f3640389815f1fe54379ca64eac071b
diff --git a/runtime/indenter_test.cc b/runtime/indenter_test.cc
index 1919e3d..1a26d7b 100644
--- a/runtime/indenter_test.cc
+++ b/runtime/indenter_test.cc
@@ -17,6 +17,8 @@
 #include "gtest/gtest.h"
 #include "indenter.h"
 
+namespace art {
+
 TEST(IndenterTest, MultiLineTest) {
   std::ostringstream output;
   Indenter indent_filter(output.rdbuf(), '\t', 2);
@@ -33,3 +35,5 @@
   input << "\n";
   EXPECT_EQ(output.str(), "\t\thello\n\t\thello again\n");
 }
+
+}  // namespace art