Auto merge of #118137 - roblabla:update-backtrace, r=ChrisDenton

Update backtrace submodule

This PR updates the backtrace submodule, avoiding panics when resolving backtraces on Windows 7:

- rust-lang/backtrace-rs#578

Fixes #117941

I ran the std unit tests locally on a Windows7 machine, and can confirm that this indeed fixes #117941.

Author: bors