glthread: use id 0 for internal buffer objects

-1 is an invalid buffer index which breaks app expectations, specifically
apitrace, which checks for return value of 0 from checking buffer bindings
to determine whether to inject user vertex buffer bindings and create functional
traces

this should fix capturing traces with drivers using glthread

fixes #8383

cc: mesa-stable

Reviewed-by: Marek Olšák <marek.olsak@amd.com>
Part-of: <https://gitlab.freedesktop.org/mesa/mesa/-/merge_requests/22293>
(cherry picked from commit a17317d2a0)

Conflicts:
	src/mesa/main/glthread_bufferobj.c

.pick_status.json

@@ -7674,7 +7674,7 @@
         "description": "glthread: use id 0 for internal buffer objects",
         "nominated": true,
         "nomination_type": 0,
-        "resolution": 0,
+        "resolution": 1,
         "main_sha": null,
         "because_sha": null,
         "notes": null

src/mesa/main/glthread_bufferobj.c

@@ -34,8 +34,9 @@ new_upload_buffer(struct gl_context *ctx, GLsizeiptr size, uint8_t **ptr)
 {
    assert(ctx->GLThread.SupportsBufferUploads);
 
+   /* id 0 is used to avoid returning invalid binding values to apps */
    struct gl_buffer_object *obj =
-      _mesa_bufferobj_alloc(ctx, -1);
+      _mesa_bufferobj_alloc(ctx, 0);
    if (!obj)
       return NULL;