Support for new double colon expressions in type checker

Despite the fact that the LHS of a double colon expression is now KtExpression
instead of KtUserType, we must still consider it a type for callable references
to work. Extract and reuse relevant parts of QualifiedExpressionResolver and
TypeResolver to support this behavior

compiler/testData/diagnostics/tests/callableReference/packageInLhs.kt

@@ -0,0 +1,16 @@
+// !DIAGNOSTICS: -UNUSED_EXPRESSION
+// FILE: simpleName.kt
+
+package foo
+
+fun test() {
+    <!UNRESOLVED_REFERENCE!>foo<!>::test
+}
+
+// FILE: qualifiedName.kt
+
+package foo.bar
+
+fun test() {
+    foo.<!UNRESOLVED_REFERENCE!>bar<!>::test
+}