Finding dSYM file on macOS can be very slow about locate-dwarf

[bjorn3]

bjorn3/pretty_backtrace@5be873a worked around this by adding a fast path for the case of the current executable being at target/<channel>/??? and the debuginfo being at target/<channel>/{deps,examples}. (Eg when using cargo run) It also adds a spin loop waiting for spotlight to find the debuginfo.

[luser]

We've got code to do simple path manipulation to support locating dSYM files on non-macOS systems, maybe we should try that first even on macOS, and only fall back to using Spotlight if that doesn't work?

[bjorn3]

We've got code to do simple path manipulation to support locating dSYM files on non-macOS systems, maybe we should try that first even on macOS, and only fall back to using Spotlight if that doesn't work?

Done and I also extended it to work for cargo, which doesn't put the dSYM in the same dir as the executable.