JetDiagnosticsTest migrated to TestGenerator

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

compiler/testData/diagnostics/tests/scopes/kt1078.kt

@@ -0,0 +1,16 @@
+//KT-1078 Problem with visibility in do-while
+
+package kt1078
+
+fun test() : B {
+    do {
+        val x = foo()
+    } while(x.bar()) // x is not visible here!
+    return B()
+}
+
+class B() {
+    fun bar() = true
+}
+
+fun foo() = B()