JetDiagnosticsTest migrated to TestGenerator

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

compiler/testData/diagnostics/tests/NamespaceInExpressionPosition.kt

@@ -0,0 +1,12 @@
+
+package foo
+
+class X {}
+
+val s = <!EXPRESSION_EXPECTED_NAMESPACE_FOUND!>java<!>
+val ss = <!NO_CLASS_OBJECT!>System<!>
+val sss = <!NO_CLASS_OBJECT!>X<!>
+val xs = java.<!EXPRESSION_EXPECTED_NAMESPACE_FOUND!>lang<!>
+val xss = java.lang.<!NO_CLASS_OBJECT!>System<!>
+val xsss = foo.<!NO_CLASS_OBJECT!>X<!>
+val xssss = <!EXPRESSION_EXPECTED_NAMESPACE_FOUND!>foo<!>