Unify emu.setislagged, emu.setlagcount, and tastudio.setlag

Summary

There are three separate ways of looking at lag in the Hawk Lua API: the lag flag (emu.setislagged), lag counter (emu.setlagcount), and TAStudio red bars (tastudio.setlag). These three values should be the three different ways of looking at the same information, but are in fact completely unrelated. There should be one simple setlag call that keeps all these values in sync.

Repro

while true do
    emu.setislagged(math.random() < 0.5)
    emu.setlagcount(math.random() * 1000)
    tastudio.setlag(emu.framecount(), math.random() < 0.5)

    emu.frameadvance()
end

Host env.

• BizHawk 2.10.0 Windows 10

Start by tracing the Lua API entry points emu.setislagged, emu.setlagcount, and tastudio.setlag, then compare how each value is stored and updated. Confirm the intended shared lag state and verify that one setlag call keeps the lag flag, counter, and TAStudio red bars synchronized.