+++ This bug was initially created as a clone of Bug #1841124 +++

So given recent discussions I attempted to run mach jstests --run-slow-tests locally, and discovered at least one test case which has been broken for a while (Bug 1841118)

Running an opt-debug configuration, here were my results:

REGRESSIONS
non262/extensions/clone-complex-object.js
non262/Function/regress-338121-03.js
TIMEOUTS
non262/extensions/regress-351448.js
non262/extensions/regress-330569.js
non262/extensions/regress-345967.js
non262/RegExp/regress-307456.js
non262/RegExp/regress-330684.js
non262/GC/regress-346794.js
non262/Array/regress-465980-02.js
non262/Array/regress-322135-02.js
non262/Array/regress-322135-04.js
non262/Array/regress-322135-03.js

I'll open bugs for the regressions, and we'll have to investigate the timeouts.