Change custom script examples file extensions:

fixes shadowing of the gradle script definitions after these example
script defs are loaded via discovery mechanisms

libraries/examples/scripting/jvm-maven-deps/host/testData/hello-unresolved-junit.scriptwithdeps.kts

@@ -0,0 +1,5 @@
+
+org.junit.Assert.assertTrue(true)
+
+println("Hello, World!")
+