Default to usejit:true.

Manually verified places that could be affected (go/lem, buildbots, CTS).
Also adjust two tests expecting JIT.

bug: 64164063
Test: m and tests
Change-Id: I6dc441f0f58203546480a0f7220ad4d9cd593fd3
diff --git a/test/knownfailures.json b/test/knownfailures.json
index a280f85..f71e936 100644
--- a/test/knownfailures.json
+++ b/test/knownfailures.json
@@ -246,7 +246,7 @@
                   "613-inlining-dex-cache",
                   "626-set-resolved-string",
                   "638-checker-inline-cache-intrinsic"],
-        "variant": "trace  | stream",
+        "variant": "trace | stream",
         "description": ["These tests expect JIT compilation, which is",
                         "suppressed when tracing."]
     },
@@ -257,6 +257,11 @@
                         "suppressed when tracing."]
     },
     {
+        "tests": "638-checker-inline-cache-intrinsic",
+        "variant": "interpreter | interp-ac",
+        "description": ["Test expects JIT compilation"]
+    },
+    {
         "tests": "597-deopt-invoke-stub",
         "variant": "speed-profile | interp-ac | interpreter | optimizing | trace | stream",
         "description": ["This test expects JIT compilation and no AOT for",