ART: Some Quick cleanup

Make several fields const in CompilationUnit. May benefit some Mir2Lir
code that repeats tests, and in general immutability is good.

Remove compiler_internals.h and refactor some other headers to reduce
overly broad imports (and thus forced recompiles on changes).

Change-Id: I898405907c68923581373b5981d8a85d2e5d185a
diff --git a/compiler/dex/quick/local_optimizations.cc b/compiler/dex/quick/local_optimizations.cc
index e0f4691..e573899 100644
--- a/compiler/dex/quick/local_optimizations.cc
+++ b/compiler/dex/quick/local_optimizations.cc
@@ -14,9 +14,10 @@
  * limitations under the License.
  */
 
-#include "dex/compiler_internals.h"
 #include "dex/quick/mir_to_lir-inl.h"
 
+#include "base/logging.h"
+
 namespace art {
 
 #define DEBUG_OPT(X)