dex2oat: Accept .dm files.

And locate primary.vdex in it to do fast verification.

bug: 63920015
Test: 674-HelloWorld-Dm
Change-Id: If920a6c7e4856a047a24bd30b049ef1ee16d7c1f
diff --git a/test/run-test b/test/run-test
index 75fe15c..bca5408 100755
--- a/test/run-test
+++ b/test/run-test
@@ -421,6 +421,9 @@
     elif [ "x$1" = "x--vdex" ]; then
         run_args="${run_args} --vdex"
         shift
+    elif [ "x$1" = "x--dm" ]; then
+        run_args="${run_args} --dm"
+        shift
     elif [ "x$1" = "x--vdex-filter" ]; then
         shift
         filter=$1