Remove vim modeline, move current_pause_determined to gc

[qinsoon]

Minor fixes to the tracing scripts:

• Remove vim modeline at the end of the bt file. Otherwise I got an error.

  ERROR: syntax error, unexpected end predicate, expecting {
  // vim: ft=bpftrace ts=4 sw=4 sts=4 et
  ~
  

• Move concurrent_pause_determined in enrich_metadata from wp to gc. It should add args for GCs, not work packets.

[wks]

LGTM