glsl: Address rest of feedback

src/shader_recompiler/profile.h

@@ -97,6 +97,8 @@ struct Profile {
     /// Fragment outputs have to be declared even if they are not written to avoid undefined values.
     /// See Ori and the Blind Forest's main menu for reference.
     bool need_declared_frag_colors{};
+    /// Prevents fast math optimizations that may cause inaccuracies
+    bool need_fastmath_off{};
 
     /// OpFClamp is broken and OpFMax + OpFMin should be used instead
     bool has_broken_spirv_clamp{};