Allow defining gradle test params via cli argument
Allow defining gradle test params via cli argument

For Elasticsearch x-plugin packaging tests we need a different gradle
command.

This commit introduces an optional cli argument (-g|--gradleoptstring)
that can be used to set the gradle parameters to execute tests.

Relates https://github.com/elastic/infra/issues/1518

Original commit: elastic/x-pack-elasticsearch@3a32e323ae7480726d3f658c428204d276a81439

scorpionvicky/elasticsearch,scorpionvicky/elasticsearch,uschindler/elasticsearch,robin13/elasticsearch,gfyoung/elasticsearch,gfyoung/elasticsearch,coding0011/elasticsearch,uschindler/elasticsearch,coding0011/elasticsearch,HonzaKral/elasticsearch,gfyoung/elasticsearch,gfyoung/elasticsearch,GlenRSmith/elasticsearch,uschindler/elasticsearch,uschindler/elasticsearch,strapdata/elassandra,robin13/elasticsearch,GlenRSmith/elasticsearch,gingerwizard/elasticsearch,uschindler/elasticsearch,gingerwizard/elasticsearch,coding0011/elasticsearch,GlenRSmith/elasticsearch,strapdata/elassandra,HonzaKral/elasticsearch,HonzaKral/elasticsearch,gingerwizard/elasticsearch,nknize/elasticsearch,scorpionvicky/elasticsearch,gingerwizard/elasticsearch,robin13/elasticsearch,coding0011/elasticsearch,nknize/elasticsearch,nknize/elasticsearch,gingerwizard/elasticsearch,HonzaKral/elasticsearch,vroyer/elassandra,scorpionvicky/elasticsearch,strapdata/elassandra,robin13/elasticsearch,coding0011/elasticsearch,scorpionvicky/elasticsearch,GlenRSmith/elasticsearch,robin13/elasticsearch,strapdata/elassandra,gingerwizard/elasticsearch,gingerwizard/elasticsearch,nknize/elasticsearch,GlenRSmith/elasticsearch,strapdata/elassandra,nknize/elasticsearch,vroyer/elassandra,vroyer/elassandra,gfyoung/elasticsearch