tests/extra_coverage: Update for sys.modules addition.

tests/unix/extra_coverage.py.exp

@@ -21,7 +21,7 @@ ame__
 __name__        path            argv            version
 version_info    implementation  platform        byteorder
 maxsize         exit            stdin           stdout
-stderr          exc_info        print_exception
+stderr          modules         exc_info        print_exception
 ementation
 # attrtuple
 (start=1, stop=2, step=3)