Remove unused PartialOrd/Ord from bootstrap

[Kobzol]

It was just wasting compile-time. There is one remaining "old" bootstrap test that uses the Ord impl on one test step, I'll remove that later.

r? @jieyoxu

[rustbot]

Failed to set assignee to jieyoxu: invalid assignee

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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.

[Kobzol]

That's what I get for creating PRs from the CLI without auto-completion..

r? @jieyouxu