report: rename location to trigger

trigger more accurately describes the use of the field.
Previously, location was just the name of the C++ function
that called TriggerNodeReport().

PR-URL: https://github.com/nodejs/node/pull/26386


Reviewed-By: Richard Lau <riclau@uk.ibm.com>
Reviewed-By: James M Snell <jasnell@gmail.com>