gl: Hardware occlusion stats; Minor fixes

[kd-11]

• Implements zcull occlusion stats using native occlusion queries.
• Implements conditional rendering as well using the emulated zcull unit
• Also adds conditional shared locks that take a flag for consideration to avoid recursive lock acquisition

Zcull occlusion statistics are used by games to determine whether a section of the world is visible or not. Currently we just return true for everything and hope for the best. This PR implements this functionality using opengl. It is always active whenever a game touches zcull stats though, so if any slowdown is experienced, please let me know so we can work around that.

[mention-bot]

@kd-11, thanks for your PR! By analyzing the history of the files in this pull request, we identified @vlj, @Nekotekina and @raven02 to be potential reviewers.

[kamer1337]

master:

your pr:

in some areas the color look wrong

log from both
thp8.zip

[kd-11]

@kamer1337 The only thing that could have affected visual output in this game can only be moving the s1 data type although that wouldve meant the game crashed before. There are no (intentional) changes to any of the output code. If vertex attribute switching caused the regression, it should be resolved with the next PR.
As such I would ask that you provide the renderdoc trace (v 0.33) before and after this PR to help with narrowing down the exact cause. I have opened a tracker here #3165