JetDiagnosticsTest migrated to TestGenerator

- test data files renamed from *.jet to *.kt

compiler/testData/diagnostics/tests/regressions/kt716.kt

@@ -0,0 +1,16 @@
+// KT-716 Type inference failed
+
+class TypeInfo<T>
+
+fun <T> typeinfo() : TypeInfo<T> = null <!CAST_NEVER_SUCCEEDS!>as<!> TypeInfo<T>
+
+fun <T> TypeInfo<T>.getJavaClass() : java.lang.Class<T> {
+    val t : java.lang.Object = this <!CAST_NEVER_SUCCEEDS!>as<!> java.lang.Object
+    return <!UNCHECKED_CAST!>t.getClass() as java.lang.Class<T><!> // inferred type is Object but Serializable was expected
+}
+
+fun getJavaClass<T>() = typeinfo<T>().getJavaClass()
+
+fun main(args : Array<String>) {
+    System.out.println(getJavaClass<String>())
+}