As outlined in https://bugzilla.mozilla.org/show_bug.cgi?id=1599197, Mozilla currently spends roughly $2700/month on autoland, and $1100/month on try to maintain test and builds for linux32.
The test set run against linux32 is quite limited due to previous decision (https://groups.google.com/forum/#!topic/mozilla.dev.platform/82cCNuWcXCk) to deprecate much of the linux32 test suite from Firefox 69.
Much of the data and assumptions from the previous decision still applies here.
This proposed change does not mean the discontinuation of linux32 tests and builds. However, the aim is to better target the build and tests where it has the maximum impact in try/mozilla-central.