Makefile.global assigns this prerequisite to every target named "check",
but similar targets must mention it explicitly.  Affected targets
failed, tested $PATH binaries, or tested a stale temporary installation.
The src/test/modules examples worked properly when called as "make -C
src/test/modules/$FOO check", but "make -j" allowed the test to start
before the temporary installation was in place.  Back-patch to 9.5,
where commit dcae5fac introduced the
shared temp-install.