Set frame->static_info in allocate_frame

So it's there right from the start. If the spesh log entry fills up
the log and causes it to be sent, then we might have a frame with no
static_info on the temp roots stack. This can cause a NULL pointer
dereference inside the GC. We could NULL-guard it there, but it's
less work to just make sure that situation can never happen.

src/core/frame.c

@@ -303,6 +303,9 @@ static MVMFrame * allocate_frame(MVMThreadContext *tc, MVMStaticFrame *static_fr
         frame->allocd_work = 0;
     }
 
+    /* Set static frame. */
+    frame->static_info = static_frame;
+
     /* Assign a sequence nr */
     frame->sequence_nr = tc->next_frame_nr++;
 
@@ -538,9 +541,6 @@ void MVM_frame_invoke(MVMThreadContext *tc, MVMStaticFrame *static_frame,
         }
     }
 
-    /* Set static frame. */
-    frame->static_info = static_frame;
-
     /* Store the code ref (NULL at the top-level). */
     frame->code_ref = code_ref;