Note: there is a bit of potential confusion about the difference between
/resources/builder.inc.sh (the full implementation for builder scripts),
and /resources/build/builder.inc.sh (the source script that builder
scripts should always use).
This allows us to make assumptions that will always be true for builder
scripts that may not be true for other scripts, such as setting base
folder.
Fixes#10957. The builder --debug flag appears to be passed correctly,
according to this test. This is a good test to keep, so won't remove it,
but there is something else going on in the base test.
