Fix shader bug likely introduced recently.

drivers/gles3/shaders/scene.glsl

@@ -1103,9 +1103,9 @@ LIGHT_SHADER_CODE
 		float Fr = mix(.04, 1.0, cLdotH5);
 		float Gr = G_GGX_2cos(cNdotL, .25) * G_GGX_2cos(cNdotV, .25);
 
-		float specular_brdf_NL = 0.25 * clearcoat * Gr * Fr * Dr * cNdotL;
+		float clearcoat_specular_brdf_NL = 0.25 * clearcoat * Gr * Fr * Dr * cNdotL;
 
-		specular_light += specular_brdf_NL * light_color * specular_blob_intensity * attenuation;
+		specular_light += clearcoat_specular_brdf_NL * light_color * specular_blob_intensity * attenuation;
 #endif
 	}