Add bootstrap.toml option to control debug breaking on ICEs on windows

[beepster4096]

When rustc ICEs during bootstrap on Windows, it will call DebugBreak. This is intended to trigger a Windows Error Reporting dialog that can launch a debugger. However on some setups (mine for one) this will just abort the process, hiding any ICEs on other threads as well. I also would not want to see this dialog even if it did work for me.

This PR adds a new option to bootstrap.toml rust.break-on-ice to configure this behavior. By default, it is enabled, matching the existing behavior.

[rustbot]

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[rustbot]

This PR modifies src/bootstrap/src/core/config.

If appropriate, please update CONFIG_CHANGE_HISTORY in src/bootstrap/src/utils/change_tracker.rs.

This PR modifies bootstrap.example.toml.

If appropriate, please update CONFIG_CHANGE_HISTORY in src/bootstrap/src/utils/change_tracker.rs.

[clubby789]

LGTM - r=me if you wouldn't mind squashing

[bors]

☔ The latest upstream changes (presumably #145663) made this pull request unmergeable. Please resolve the merge conflicts.

[rustbot]

This PR was rebased onto a different master commit. Here's a range-diff highlighting what actually changed.

Rebasing is a normal part of keeping PRs up to date, so no action is needed—this note is just to help reviewers.

[beepster4096]

Done! Sorry about the delay.