GPU: Implement the A2BGR10 texture format.

SDL2: Implement fullscreen. (Original PR: citra-emu/citra#3607)

Shader opcode decoding

opengl: Remove unnecessary header inclusions

ShaderGen: Implemented fsetp/kil and predicated instruction execution.

gl_resource_manager: Add missing noexcept specifiers to move constructors and assignment operators

gl_rasterizer_cache: Make MatchFlags an enum class

Each predicated instruction will be wrapped in an `if (predicate) { instruction_body; }` in the GLSL, where `predicate` is one of the predicate boolean variables previously set by fsetp.

Predicate variables are now added to the generated shader code in the form of 'pX' where X is the predicate id.
These predicate variables are initialized to false on shader startup and are set via the fsetp instructions.

TODO:

* Not all the comparison types are implemented.
* Only the single-predicate version is implemented.

resource_limit: Make ResourceTypes an enum class

core: Relocate g_service_manager to the System class

Standard library containers may use std::move_if_noexcept to perform
move operations. If a move cannot be performed under these
circumstances, then a copy is attempted. Given we only intend for these
types to be move-only this can be somewhat problematic. By defining
these to be noexcept we prevent cases where copies may be attempted.

Prevents implicit conversions and scope pollution.

Converts the service manager from a global into an instance-based
variable.

Prevents enum identifiers from leaking into the surrounding scope.

Service/VI: stub SetLayerVisibility, fix GetDisplayResolution output

The 'sched' instruction has a very convoluted encoding, but fortunately it seems to only appear on a fixed interval (once every 4 instructions).

math_util: Remove the Clamp() function

common_types: Minor changes

C++17 adds clamp() to the standard library, so we can remove ours in
favor of it.

externals: Update dynarmic to HEAD

service: Use nested namespace specifiers where applicable

common/thread: Remove unnecessary feature checking for thread_local

common_funcs: Remove check for VS versions that we don't even support

common_funcs: Remove ARRAY_SIZE macro

vector_math: Remove AsArray() and Write() functions from Vec[2,3,4]

common: Remove code_block.h

These are all unused and the Write() ones should arguably not even be in the interface. There are better ways to provide this if we ever need it (like iterators).

We use dynarmic, so this is unued. Anything else we need will likely use Xbyak, so
this header isn't necessary any more.

Every compiler we require already supports it.