Revert "Test C++ out-of-line operator functions (#32081)"

This reverts commit f7473a7.

Author: MForster

test/Interop/Cxx/operators/Inputs/module.modulemap

@@ -1,7 +1,3 @@
 module NonMemberInline {
   header "non-member-inline.h"
 }
-
-module NonMemberOutOfLine {
-  header "non-member-out-of-line.h"
-}