core: Reduce string copies in GetGameFileFromPath()

CMakeLists: disable -Winvalid-offsetof

This Clang warning complains when offsetof is used on a
non-standard-layout type (i.e. any class using various C++ features),
even though it works fine (and is not undefined behavior as of C++17).

core: Eliminate remaining usages of the global system instance

Removes all remaining usages of the global system instance. After this,
migration can begin to migrate to being constructed and managed entirely
by the various frontends.

savedata_factory: Eliminate usage of the global system instance

Now there's only two meaningful instances left in core.

service: Eliminate usages of the global system instance

Completely removes all usages of the global system instance within the
services code by passing in the using system instance to the services.

codec: Fix `pragma GCC diagnostic pop` missing corresponding push

Eliminates some minor string churn where applicable. Also eliminates an
unnecessary vector copy.

nvdrv, video_core: Don't index out of bounds when given invalid syncpoint ID

nvservices: Reintroducee IoctlCtrl

input_common: unbreak -Werror with Clang

error: unknown warning option '-Werror=unused-but-set-parameter'; did you mean '-Werror=unused-parameter'? [-Werror,-Wunknown-warning-option]
error: unknown warning option '-Werror=unused-but-set-variable'; did you mean '-Werror=unused-const-variable'? [-Werror,-Wunknown-warning-option]

Overhaul EmuWindow::PollEvents to fix yuzu-cmd calling SDL_PollEvents off main thread

renderer_vulkan: Implement alpha testing

configure_input_player: Use the NpadStyleSet to limit the available controllers shown

audren: Make use of nodiscard, rework downmixing, release all buffers

core: cpu_manager: Fix shutdown crash when closing before emulation starts.

Co-Authored-By: Rodrigo Locatti <reinuseslisp@airmail.cc>

Used by various textures in many titles, e.g.  SSBU menu.

Allow to dial any angle with digital joystick

core: Refactor loader and implement ExecuteProgram

- This is used by Super Mario 3D All-Stars.

* hle: services: Fix a crash with improper NVFlinger lifetime management.

- This crash would happen when attempting to shutdown yuzu early on in boot.

- Use .at() instead of raw indexing when dealing with untrusted indices.

- For the special case of WaitFence with syncpoint id UINT32_MAX,
  instead of crashing, log an error and ignore.  This is what I get when
  running Super Mario Maker 2.

decoder/image: Fix incorrect G24R8 component sizes in GetComponentSize()

core: Make use of [[nodiscard]] with the System class

svc: Remove unnecessary [[maybe_unused]] tag

Fixes regression caused by #4907 which caused games like Breath of the Wild 1.0.0 not to boot.

input_common: Add more missing [[maybe_unused]] from #4927.