[libcxx][dsl] Fix mutable default argument warning
authorAlex Richardson <Alexander.Richardson@cl.cam.ac.uk>
Mon, 5 Oct 2020 21:54:22 +0000 (22:54 +0100)
committerAlex Richardson <Alexander.Richardson@cl.cam.ac.uk>
Mon, 5 Oct 2020 22:23:30 +0000 (23:23 +0100)
commite426ae2bd5e04ca57f36bfb64a5a466a6797cea1
treee37c4f9cc9f56bbb8d163c3c05e894b360bfaaca
parent4da4e7cb2092c80ccb5c6c7e013b0f103c14d3e0
[libcxx][dsl] Fix mutable default argument warning

This is flagged by PyCharm and can cause subtle bugs. While changing this
also re-sort the imports and add missing ones.

Reviewed By: #libc, ldionne

Differential Revision: https://reviews.llvm.org/D88816
libcxx/utils/libcxx/test/dsl.py