[FE] Add case with ambiguous generic call

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

@@ -10,6 +10,8 @@ interface C2 : Common {
 
 fun Common.supertypeExtension() {}
 
+fun <T : Common> T.supertypeExtensionGeneric() {}
+
 context(Common)
 fun supertypeContextual() {}
 
@@ -18,5 +20,6 @@ fun test() {
     <!OVERLOAD_RESOLUTION_AMBIGUITY!>supertypeMember<!>()
     <!OVERLOAD_RESOLUTION_AMBIGUITY!>member<!>()
     <!AMBIBIGUOS_CALL_WITH_IMPLICIT_CONTEXT_RECEIVER!>supertypeExtension()<!>
+    <!AMBIBIGUOS_CALL_WITH_IMPLICIT_CONTEXT_RECEIVER!>supertypeExtensionGeneric()<!>
     <!MULTIPLE_ARGUMENTS_APPLICABLE_FOR_CONTEXT_RECEIVER!>supertypeContextual()<!>
 }