linux: Better GPU debugging (#14706)

Release Notes:

- linux: Added GPU information to `editor: Copy System Specs to
Clipboard`
- linux: Show a prominant warning before running under llvmpipe and
similar.

crates/gpui/src/platform/test/window.rs

@@ -1,7 +1,7 @@
 use crate::{
-    AnyWindowHandle, AtlasKey, AtlasTextureId, AtlasTile, Bounds, DispatchEventResult, Pixels,
-    PlatformAtlas, PlatformDisplay, PlatformInput, PlatformInputHandler, PlatformWindow, Point,
-    Size, TestPlatform, TileId, WindowAppearance, WindowBackgroundAppearance, WindowBounds,
+    AnyWindowHandle, AtlasKey, AtlasTextureId, AtlasTile, Bounds, DispatchEventResult, GPUSpecs,
+    Pixels, PlatformAtlas, PlatformDisplay, PlatformInput, PlatformInputHandler, PlatformWindow,
+    Point, Size, TestPlatform, TileId, WindowAppearance, WindowBackgroundAppearance, WindowBounds,
     WindowParams,
 };
 use collections::HashMap;
@@ -273,6 +273,10 @@ impl PlatformWindow for TestWindow {
     fn start_window_move(&self) {
         unimplemented!()
     }
+
+    fn gpu_specs(&self) -> Option<GPUSpecs> {
+        None
+    }
 }
 
 pub(crate) struct TestAtlasState {