testing and plugin updates for 9.0 (pre-PR) This brings in the first batch of testing updates for the next release. The main bulk of these is Daniel and Thomas' cleanups of the qtest timeouts and allowing meson control them. There are a few minor tweaks I've made to some avocado and gitlab tests. The big update is support for reading register values in TCG plugins. After feedback from Akihiko I've left all the smarts to the plugin and made the interface a simple "all the registers" dump. There is a follow on patch to make the register code a little more efficient by checking disassembly. However we can leave the door open for future API enhancements if the translator ever learns to reliably know when registers might be touched. v2 -- - Review feedback for register API - readthedocs update - add expectation docs for plugins The following still need review: docs/devel: document some plugin assumptions docs/devel: lift example and plugin API sections up contrib/plugins: optimise the register value tracking contrib/plugins: extend execlog to track register changes contrib/plugins: fix imatch plugins: add an API to read registers gdbstub: expose api to find registers readthodocs: fully specify a build environment gitlab: include microblazeel in testing tests/avocado: use snapshot=on in kvm_xen_guest