Feature request: Duplicate/multiply a flaky test

[cgwalters]

Motivation

In order to debug a flaky test, it'd be useful to be able to run it multiple times directly. The same motivation as I did for a different test framework: coreos/coreos-assembler#1615

You'd usually want to do this while filtering to one (or just a few) tests, like

$ cargo nextest run --multiply 20 test_something

Proposal

Ability to run a test multiple times within the same framework.

Alternatives

One can do this manually by executing in different terminals, but it does mean that some duplicate work happens in each one to spin up the whole runner infrastructure.

Additional context

No response

[sunshowers]

Yep -- #2219 would be really nice to have.

[cgwalters]

Ah, makes sense this is a duplicate; I tried searching for the keywords "multiply" (what I used in that other framework) and "duplicate" but didn't think of "stress".