JetDiagnosticsTest migrated to TestGenerator

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

compiler/testData/diagnostics/tests/Basic.kt

@@ -0,0 +1,15 @@
+fun foo(<!UNUSED_PARAMETER!>u<!> : Unit) : Int = 1
+
+fun test() : Int {
+    foo(<!TYPE_MISMATCH!>1<!>)
+    val <!UNUSED_VARIABLE!>a<!> : () -> Unit = {
+        foo(<!TYPE_MISMATCH!>1<!>)
+    }
+    return 1 <!NONE_APPLICABLE!>-<!> "1"
+}
+
+class A() {
+    val x : Int = <!TYPE_MISMATCH!>foo1(<!TOO_MANY_ARGUMENTS, UNRESOLVED_REFERENCE!>xx<!>)<!>
+}
+
+fun foo1() {}