Support DATA_STALL_EVENT in StatsLog.write

The target source to send the event will be mainline module
which unable to access @hide classes/functions. And current
design of StatsLog.write only allows a specific id. Thus, add
more case to support mainline module usage.

Bug: 120452078
Test: ./out/host/linux-x86/bin/statsd_testdrive 121
      against data stall event sent from NetworkStack

Change-Id: I5a68e7e093e63cc87eae753068183215a97e022d