### Godot version

4.0.beta16

### System information

Windows 10 Pro x64, GLES3, RTX 3080 Ti (528.02)

### Issue description

In Compatibility/GLES3 back-end, shaders which use a uniform to get the normal roughness buffer cannot compile. For example, the shader:
```glsl
shader_type spatial;

uniform sampler2D normal_roughness_texture : hint_normal_roughness_texture;

void fragment() {
    vec4 sample = texture(normal_roughness_texture, UV);
}
```
results in an error in the output:
```
  drivers/gles3/shader_gles3.cpp:242 - SceneShaderGLES3: Fragment shader compilation failed:
  0(890) : error C1503: undefined variable "normal_roughness_buffer"
  
  drivers/gles3/shader_gles3.cpp:342 - Method/function failed.
```

If I switch over to the Mobile or Forward+ backends, there is no shader compilation error.

### Steps to reproduce

Open the attached reproduction in the 4.0.beta16 editor.

When the scene is opened, the error is produced automatically:
1. Open `scene.tscn`
2. Open Output to review error

When the scene is saved with any changes made to the shader, the same error is also produced:
1. Open `scene.tscn`
2. Open `example.gdshader` in the shader editor.
3. Make a compile-able change to the shader.
4. Save the scene
5. Open Output to review the error

### Minimal reproduction project

[NormalRoughnessTexture_GLES3_Error.zip](https://github.com/godotengine/godot/files/10534253/NormalRoughnessTexture_GLES3_Error.zip)

HashSet<String> kws;
	int idx = 0;
	while (keyword_list[idx].text) {
		kws.insert(keyword_list[idx].text);
		idx++;
	}
	idx = 0;
	while (builtin_func_defs[idx].name) {
		kws.insert(builtin_func_defs[idx].name);
		idx++;
	}
	for (const String &E : kws) {
		r_keywords->push_back(E);
	}
}
bool ShaderLanguage::is_control_flow_keyword(String p_keyword) {
	return p_keyword == "break" ||
			p_keyword == "case" ||
			p_keyword == "continue" ||
			p_keyword == "default" ||
			p_keyword == "do" ||
			p_keyword == "else" ||
			p_keyword == "for" ||
			p_keyword == "if" ||
			p_keyword == "return" ||
			p_keyword == "switch" ||
			p_keyword == "while";
}
void ShaderLanguage::get_builtin_funcs(List<String> *r_keywords) {