Don't always run code in Ant task tests

But when running code, do it via <java> task, not via custom testing code. Most
of the time the compiled code need not be runned, because it's irrelevant to
the Ant task itself

compiler/testData/integration/ant/jvm/helloWorld/build.log.expected

@@ -3,6 +3,7 @@ Buildfile: [TestData]/build.xml
 
 build:
   [kotlinc] Compiling [[TestData]/hello.kt] => [[Temp]/hello.jar]
+     [java] Hello, a!
 
 BUILD SUCCESSFUL
 Total time: [time]

compiler/testData/integration/ant/jvm/helloWorld/build.xml

@@ -3,5 +3,12 @@
 
     <target name="build">
         <kotlinc src="${test.data}/hello.kt" output="${temp}/hello.jar"/>
+
+        <java classname="hello.HelloPackage" fork="true">
+            <classpath>
+                <pathelement location="${temp}/hello.jar"/>
+                <pathelement location="${kotlin.runtime.jar}"/>
+            </classpath>
+        </java>
     </target>
 </project>

compiler/testData/integration/ant/jvm/helloWorld/hello.run.expected

@@ -1,4 +0,0 @@
-OUT:
-Hello, a!
-
-Return code: 0