Exposed visibility checking, a set of exposed visibility tests, some test fixes

Effective visibility mechanism introduced.
Local is considered as public, java protected as Kotlin protected, java package private as Kotlin private.

compiler/testData/diagnostics/tests/exposed/functional.kt

@@ -0,0 +1,12 @@
+internal class My
+
+class Your
+
+// Both arguments should be exposed
+fun foo(<!EXPOSED_PARAMETER_TYPE!>my: My<!>, <!EXPOSED_PARAMETER_TYPE!>f: (My) -> Unit<!>) = f(my)
+
+// Ok
+fun bar(your: Your, f: (Your) -> Unit) = f(your)
+
+// Exposed, returns My
+fun <!EXPOSED_FUNCTION_RETURN_TYPE!>gav<!>(<!EXPOSED_PARAMETER_TYPE!>f: () -> My<!>) = f()