ART: Add compiler option for code deduplication

Add --deduplicate-code and --no-deduplicate-code to ease in
experiments with deduplication, e.g., profiling.

Add dex2oat test.

Test: m test-art-host
Change-Id: Ib6c7fe082f43c5f76c8463cc563e2503c9a50480
diff --git a/dex2oat/dex2oat.cc b/dex2oat/dex2oat.cc
index 46474d2..29228a3 100644
--- a/dex2oat/dex2oat.cc
+++ b/dex2oat/dex2oat.cc
@@ -452,6 +452,9 @@
   UsageError("  --compact-dex-level=none|fast: None avoids generating compact dex, fast");
   UsageError("      generates compact dex with low compile time.");
   UsageError("");
+  UsageError("  --deduplicate-code|--no-deduplicate-code: enable|disable code deduplication.");
+  UsageError("      Deduplicated code will have an arbitrary symbol tagged with [DEDUPED].");
+  UsageError("");
   std::cerr << "See log for usage error information\n";
   exit(EXIT_FAILURE);
 }