build: Make backtraces useable in release builds

Having `panic = "abort"` and `strip = "symbols"` makes backtraces generated with `RUST_BACKTRACE=1` completely useless in release builds.

By changing these options to `panic = "unwind"` and `strip = "debuginfo"` makes backtraces usable in release builds. This will help us debug issues we are unable to reproduce, since we can ask users to set `RUST_BACKTRACE=1` and provide the logs with this option.

Cargo.toml

@@ -112,8 +112,8 @@ winapi = "0.3.9"
 # We optimize the release build for size.
 [profile.release]
 opt-level = "z"
-panic = "abort"
-strip = true      # Strip symbols from the binary.
-codegen-units = 1 # Parallel compilation prevents some optimizations.
+panic = "unwind"    # Abort makes backtraces useless.
+strip = "debuginfo" # Only strip debuginfo (not symbols) to keep backtraces useful.
+codegen-units = 1   # Parallel compilation prevents some optimizations.
 # We do not enable link-time optimizations (lto) because they cause the
 # CLI to timeout when run in Xcode Cloud.