shader_recompiler,video_core: Cleanup some GCC and Clang errors

Mostly fixing unused *, implicit conversion, braced scalar init,
fpermissive, and some others.

Some Clang errors likely remain in video_core, and std::ranges is still
a pertinent issue in shader_recompiler

shader_recompiler: cmake: Force bracket depth to 1024 on Clang
Increases the maximum fold expression depth

thread_worker: Include condition_variable

Don't use list initializers in control flow

Co-authored-by: ReinUsesLisp <reinuseslisp@airmail.cc>

src/tests/common/unique_function.cpp

@@ -17,10 +17,12 @@ struct Noisy {
     Noisy& operator=(Noisy&& rhs) noexcept {
         state = "Move assigned";
         rhs.state = "Moved away";
+        return *this;
     }
     Noisy(const Noisy&) : state{"Copied constructed"} {}
     Noisy& operator=(const Noisy&) {
         state = "Copied assigned";
+        return *this;
     }
 
     std::string state;