in src/it/MJAR-275-reproducible-module-info/verify.groovy [49:55]
long normalizeUTC( String timestamp )
{
long millis = Instant.parse( timestamp ).toEpochMilli();
Calendar cal = Calendar.getInstance();
cal.setTimeInMillis( millis );
return millis - ( cal.get( Calendar.ZONE_OFFSET ) + cal.get( Calendar.DST_OFFSET ) );
}