ART: More header cleanup - runtime.h

Remove unnecessary runtime.h includes. Refactor other headers
(move to forward declarations) to make this possible.

Test: mmma art
Change-Id: I297f0ad444ba92169edd16d8c7cbe95bb6dbb800
diff --git a/cmdline/cmdline_parser_test.cc b/cmdline/cmdline_parser_test.cc
index 1a2b9cd..9f12f64 100644
--- a/cmdline/cmdline_parser_test.cc
+++ b/cmdline/cmdline_parser_test.cc
@@ -22,6 +22,7 @@
 #include <numeric>
 #include "gtest/gtest.h"
 #include "runtime/experimental_flags.h"
+#include "runtime/runtime.h"
 
 #define EXPECT_NULL(expected) EXPECT_EQ(reinterpret_cast<const void*>(expected), \
                                         reinterpret_cast<void*>(nullptr));