Allow skipping TB2/TB3 tests using tests.tb2/tb3.skip

Change-Id: If9f16657731fa5ea06e61bf9702abe385e4fc7a1

uitest/tb3test.xml

@@ -10,7 +10,7 @@
         <path location="${tb3test.dir}/result/classes" />
     </path>
 
-    <target name="run-all-tb3-tests" description="Run all the TB3 tests (except server tests) in the project">
+    <target name="run-all-tb3-tests" unless="tests.tb3.skip" description="Run all the TB3 tests (except server tests) in the project">
         <antcall target="run-tb3-suite">
             <param name="junit.test.suite" value="com.vaadin.tests.tb3.AllTB3Tests" />
         </antcall>

uitest/test.xml

@@ -83,7 +83,7 @@
         <fail unless="com.vaadin.testbench.deployment.url" message="The 'com.vaadin.testbench.deployment.url' property must be defined." />
     </target>
 
-    <target name="run-tb2-tests" depends="check-parameters,compile-tests">
+    <target name="run-tb2-tests" depends="check-parameters,compile-tests" unless="tests.tb2.skip">
         <fileset dir="${test-output-dir}" id="tests-fileset">
             <include name="**/**.java" />
         </fileset>