Adjusts the startup and shutdown behavior of most threads in the console host to alleviate race conditions that are either exacerbated or introduced by the VT PTY threads.
* Don't trigger a frame due to circling when in the middle of a resize operation
This fixes#1795, and shined quite a bit of light on the whole conpty resize process.
* Move the Begin/End to ResizeScreenBuffer, to catch more cases.
* Apply [[nodiscard]] to functions returning error codes
- applied [[nodiscard]] for all HRESULT, LRESULT, and NTSTATUS functions
- fixed IntelliSense declaration complaints leading to function not
implemented warnings
- deleted declared but never implemented functions
- fixed unused parameter warnings
How verified:
- bcz dbg
- opencon
- testcon
- VS2019 debug build
* - use LOG_IF_FAILED where applicable
- remove use of goto
- make MakeAltRasterFont return void
* - add missing [[nodiscard]]
- remove vestigal function declarations
- fix inconsistent function declaration
