Adjust expectation for 629-vdex-speed.

debuggable disables AOT compiled code, so expect a failure there.

Test: 629-vdex-speed
Change-Id: Icc16f69940c415cc281c2abc809d92cc6b16f42a
diff --git a/test/knownfailures.json b/test/knownfailures.json
index 3762623..5f67734 100644
--- a/test/knownfailures.json
+++ b/test/knownfailures.json
@@ -81,7 +81,7 @@
     },
     {
         "tests" : "629-vdex-speed",
-        "variant": "interp-ac | interpreter | no-prebuild",
+        "variant": "interp-ac | interpreter | no-prebuild | debuggable",
         "description": "629 requires compilation."
     },
     {