Make incremental default back to false in JUnitShell

Change-Id: Ic1b23abe970561d6acbf56f6c713f88169f42207
diff --git a/user/src/com/google/gwt/junit/JUnitShell.java b/user/src/com/google/gwt/junit/JUnitShell.java
index 0bcd3ad..a4cb6aa 100644
--- a/user/src/com/google/gwt/junit/JUnitShell.java
+++ b/user/src/com/google/gwt/junit/JUnitShell.java
@@ -933,6 +933,16 @@
   }
 
   @Override
+  protected HostedModeBaseOptions createOptions() {
+    HostedModeBaseOptions options = super.createOptions();
+    // DevMode defaults to incremental because it passes the flag to the
+    // CodeServer, which is incremental by default. But for GWTTestCase
+    // we don't want an incremental-by-default behavior, so reset it here.
+    options.setCompilePerFile(false);
+    return options;
+  }
+
+  @Override
   protected boolean doStartup() {
     if (!super.doStartup()) {
       return false;