Debug bootstrap test on CI

[Flamefire]

The current failure looks like

 == FAILED: Installation ended unsuccessfully (build directory: /tmp/tmp1ec454qx/EasyBuild/4.7.1/dummy-dummy): build failed (first 300 chars): cmd " /opt/hostedtoolcache/Python/3.7.16/x64/bin/python -m pip install --prefix=/tmp/runner/200614b91caee792396c8fd6365e015e1bb9145f/eb_bootstrap/software/EasyBuild/4.7.1  --no-deps  --ignore-installed  --no-build-isolation  ." exited with exit code 1 and output:
Processing /tmp/tmp1ec454qx/EasyBuil (took 4 secs)
== Results of the build can be found in the log file(s) /tmp/eb-u9niem1r/easybuild-EasyBuild-4.7.1-20230511.110258.MiSOu.log

This isn't helpful so in a first step this prints out the log file in case of error.

[branfosj]

See #4255. The bootstrap is deprecated and will be removed in EB5, so we'll just remove the workflow that tests it instead.