Option to set end_date for performance testing dag. (#8817)
Option to set end_date for performance testing dag. (#8817)

I wanted an option to run a specific number of dag runs to completion,
so this feature lets me control the end_date of the dag without having
to know exactly what value it would have.

The "is string" check is more simplistic than it needs to be, but it's
Good Enough for now for an optional feature.
Acehaidrey/incubator-airflow,apache/airflow,cfei18/incubator-airflow,mistercrunch/airflow,bolkedebruin/airflow,dhuang/incubator-airflow,apache/incubator-airflow,DinoCow/airflow,danielvdende/incubator-airflow,mistercrunch/airflow,mrkm4ntr/incubator-airflow,cfei18/incubator-airflow,airbnb/airflow,wooga/airflow,mistercrunch/airflow,danielvdende/incubator-airflow,Acehaidrey/incubator-airflow,apache/incubator-airflow,nathanielvarona/airflow,nathanielvarona/airflow,danielvdende/incubator-airflow,Acehaidrey/incubator-airflow,bolkedebruin/airflow,danielvdende/incubator-airflow,lyft/incubator-airflow,cfei18/incubator-airflow,danielvdende/incubator-airflow,dhuang/incubator-airflow,nathanielvarona/airflow,mrkm4ntr/incubator-airflow,apache/airflow,dhuang/incubator-airflow,nathanielvarona/airflow,bolkedebruin/airflow,apache/airflow,bolkedebruin/airflow,cfei18/incubator-airflow,sekikn/incubator-airflow,apache/incubator-airflow,wooga/airflow,lyft/incubator-airflow,Acehaidrey/incubator-airflow,Acehaidrey/incubator-airflow,mrkm4ntr/incubator-airflow,mistercrunch/airflow,sekikn/incubator-airflow,DinoCow/airflow,airbnb/airflow,dhuang/incubator-airflow,Acehaidrey/incubator-airflow,airbnb/airflow,bolkedebruin/airflow,apache/airflow,lyft/incubator-airflow,lyft/incubator-airflow,apache/incubator-airflow,danielvdende/incubator-airflow,sekikn/incubator-airflow,cfei18/incubator-airflow,nathanielvarona/airflow,apache/airflow,mrkm4ntr/incubator-airflow,wooga/airflow,sekikn/incubator-airflow,airbnb/airflow,DinoCow/airflow,cfei18/incubator-airflow,apache/airflow,wooga/airflow,nathanielvarona/airflow,DinoCow/airflow