Patch to fix a segfault while printing in LLDB

Hello,

I probably should have sent this email before trying to work on this and before submitting a diff, but better late than never.

Recently I encountered a segfault while using LLDB. I tracked down the issue in source/Host/common/Editline.cpp, and have uploaded a diff with what I believe is the correct fix. I originally have added reviewers based on people who committed to the same file in the past few months, but I’m unsure of who might be best to review this. If you are familiar with this portion of the codebase and have some time, I would appreciate a review. The relevant details (reproduction, justification of my fix, etc) are in the summary of the diff.

The diff in question is here: https://reviews.llvm.org/D32421