Disable 629-vdex-speed test on trace config

trace config disables AOT code, so the test isn't expected to work.

Test: art/testrunner.py -t 629 --trace
Change-Id: Ib2252528fe50840df15cfc610996d030b7558811
diff --git a/test/knownfailures.json b/test/knownfailures.json
index 2971b27..f3b98c9 100644
--- a/test/knownfailures.json
+++ b/test/knownfailures.json
@@ -81,7 +81,7 @@
     },
     {
         "tests" : "629-vdex-speed",
-        "variant": "interp-ac | interpreter | no-prebuild | debuggable",
+        "variant": "interp-ac | interpreter | no-prebuild | debuggable | trace",
         "description": "629 requires compilation."
     },
     {