glsl: Add boolean reference workaround

src/shader_recompiler/profile.h

@@ -67,6 +67,8 @@ struct Profile {
     bool has_gl_precise_bug{};
     /// Some drivers do not properly support floatBitsToUint when used on cbufs
     bool has_gl_cbuf_ftou_bug{};
+    /// Some drivers poorly optimize boolean variable references
+    bool has_gl_bool_ref_bug{};
     /// Ignores SPIR-V ordered vs unordered using GLSL semantics
     bool ignore_nan_fp_comparisons{};