Revive ART run-test 648-many-direct-methods for non-debug mode.

This test is stressing dex2oatd and fails on too many configurations,
but works fine with dex2oat.

Test: art/test/testrunner/testrunner.py --debug --ndebug -t 648-many-direct-methods
Bug: 33650497
Change-Id: Ie2e4ba3c14318e3f3c584a032012bcb93d88ebc7
diff --git a/test/knownfailures.json b/test/knownfailures.json
index f7fb357..ab5bc0d 100644
--- a/test/knownfailures.json
+++ b/test/knownfailures.json
@@ -677,5 +677,11 @@
             "Tests that have verify-at-runtime classes, but being compiled when using vdex."
         ],
         "variant": "speed-profile"
+    },
+    {
+        "tests": "648-many-direct-methods",
+        "variant": "debug",
+        "description": "Test disabled in debug mode because of dex2oatd timeouts.",
+        "bug": "b/33650497"
     }
 ]