Move Specification to InternedData

Allowing multiple producer to emit GPU specification.

Test: gpu_render_stages_interned_spec.textproto

Change-Id: If22cc6139df403fbca776cd51fbdfba1ba5d29c0

BUILD

diff --git a/BUILD b/BUILD
index a5ca692..3e761b2 100644
--- a/BUILD
+++ b/BUILD
@@ -2269,6 +2269,8 @@
         PERFETTO_CONFIG.proto_library_visibility,
     ],
     deps = [
+        ":protos_perfetto_common_protos",
+        ":protos_perfetto_trace_gpu_protos",
         ":protos_perfetto_trace_profiling_protos",
         ":protos_perfetto_trace_track_event_protos",
     ],