Enable the full test suite for pull requests

[psss]

We'd like to move the whole coverage of /tests/full into pull request testing. This issue will track the progress of the migration.

Related pull requests:

• Enable /plans/provision/virtual for pull requests #2558
• Enable the /tests/discover/libraries test #2222
• Use the PROVISION_HOW variable in provision plans #2688
• Enable additional_coverage tests for pull requests #2700
• Remove mention about the full test suite from docs #2701

Additional coverage which is run only with how=full follows:

Tagged with additional_coverage

• /tests/core/escaping
• /tests/core/spaces
• /tests/discover/distgit
• /tests/discover/libraries
• /tests/execute/duration
• /tests/execute/nonroot
• /tests/execute/reboot/reuse-provision
• /tests/execute/reboot/shorten-timeout
• /tests/execute/rsync
• /tests/execute/tty
• /tests/execute/upgrade/full
• /tests/finish/ansible
• /tests/login/ready
• /tests/multihost/web
• /tests/prepare/ansible
• /tests/prepare/install
• /tests/prepare/recommend
• /tests/provision/reboot
• /tests/provision/ssh-options
• /tests/provision/virtual.testcloud
• /tests/pull/results
• /tests/pull/simple
• /tests/run/shell
• /tests/run/worktree
• /tests/security/ansible
• /tests/test/check/avc
• /tests/test/check/dmesg
• /tests/test/debug

/plans/features/advanced

• /tests/execute/reboot/reuse-provision
• /tests/execute/reboot/shorten-timeout
• /tests/execute/upgrade/full
• /tests/multihost/web

/plans/features/steps/discover

• /tests/discover/libraries

/plans/features/steps/execute

• /tests/execute/nonroot
• /tests/execute/rsync

/plans/features/steps/the-rest

• /tests/provision/ssh-options
• /tests/provision/virtual.testcloud

smoke test for provision connect

• /tests/execute/reboot/reuse-provision