Reword the permanent client-window refusal text and drop the stale P12 tag.

tools/device_bench/p6/README.md

@@ -116,7 +116,7 @@ indistinguishable from a run that produced none.
   as an explicit `--env MOBILEGL_TRANSPORT=…` and verifies it from the library's log.
 - **`MOBILEGL_RETRACE_USE_PBUFFER` must be in the CI script's environment**, not passed as `--env` —
   `trace-replay-ci.sh` reads it itself to decide the surface shape. Without it the `spawn` arm dies
-  with `Fatal{UnmigratedSurface, "AndroidNativeWindow@P12"}`, because an `ANativeWindow*` means
+  with `Fatal{UnmigratedSurface, "AndroidNativeWindow:use-MOBILEGL_IPC_SURFACE=server"}`, because an `ANativeWindow*` means
   nothing in the server's process (Rule H).
 - **`MOBILEGL_TRACE_SKIP_INSTALL=1`** keeps the script's own `adb install` out of the window. The
   session installs once itself and waits for `dex2oat` to exit first: an `am_kill … due to

tools/device_bench/p6/ab_session.py

@@ -491,7 +491,7 @@ class Arm:
 
         That is fatal on the spawn arm and only there: an ANativeWindow* is a pointer into the
         CLIENT's process and the wire refuses it by name (Rule H). Measured on this tree - the spawn
-        arm died with `Fatal{UnmigratedSurface, "AndroidNativeWindow@P12"}` published as a
+        arm died with `Fatal{UnmigratedSurface, "AndroidNativeWindow:use-MOBILEGL_IPC_SURFACE=server"}` published as a
         SessionFault, and the same run passes as soon as the variable is in the script's environment.
         """
         return {"MOBILEGL_RETRACE_USE_PBUFFER": "1"}