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/etc/run-test-jar b/test/etc/run-test-jar
index 713fd35..5c4ad21 100755
--- a/test/etc/run-test-jar
+++ b/test/etc/run-test-jar
@@ -588,7 +588,7 @@
 fi
 
 if [ "$INTERPRETER" = "y" ]; then
-    INT_OPTS="-Xint"
+    INT_OPTS="${INT_OPTS} -Xint"
     if [ "$VERIFY" = "y" ] ; then
       INT_OPTS="${INT_OPTS} -Xcompiler-option --compiler-filter=quicken"
       COMPILE_FLAGS="${COMPILE_FLAGS} --compiler-filter=quicken"
@@ -604,7 +604,7 @@
 fi
 
 if [ "$JIT" = "y" ]; then
-    INT_OPTS="-Xusejit:true"
+    INT_OPTS="${INT_OPTS} -Xusejit:true"
     if [ "$VERIFY" = "y" ] ; then
       INT_OPTS="${INT_OPTS} -Xcompiler-option --compiler-filter=quicken"
       COMPILE_FLAGS="${COMPILE_FLAGS} --compiler-filter=quicken"
@@ -613,6 +613,8 @@
       COMPILE_FLAGS="${COMPILE_FLAGS} --compiler-filter=assume-verified"
       DEX_VERIFY="${DEX_VERIFY} -Xverify:none"
     fi
+else
+    INT_OPTS="${INT_OPTS} -Xusejit:false"
 fi
 
 JNI_OPTS="-Xjnigreflimit:512 -Xcheck:jni"