The docbuild often fails, for example currently on cygwin (#30796), and then the testsuite is not run.

Depends on #29124

CC: @jhpalmieri @kliem @dimpase

Component: build

Author: Matthias Koeppe

Branch/Commit: 0dca776

Reviewer: Jonathan Kliem

Issue created by migration from https://trac.sagemath.org/ticket/31084