[FE] Relax the "no subtyping between context receivers" limitation

compiler/testData/diagnostics/tests/extensions/contextReceivers/genericOuterClass.kt

@@ -4,10 +4,10 @@ context(Collection<P>) class B<P>
 
 fun Int.foo() {
     A<Int>()
-    <!UNRESOLVED_REFERENCE_WRONG_RECEIVER!>A<!><String>()
+    <!NO_CONTEXT_RECEIVER!>A<String>()<!>
 }
 
 fun Collection<Int>.bar() {
     B<Int>()
-    <!UNRESOLVED_REFERENCE_WRONG_RECEIVER!>B<!><String>()
+    <!NO_CONTEXT_RECEIVER!>B<String>()<!>
 }