ElasticReindexIT: Increase -Xmx to 1024m to fix test
ElasticReindexIT: Increase -Xmx to 1024m to fix test

For Java 8 the test fails with 512 MB of maximum heap size and takes
*really* long. Increasing this value to 1024 MB passes the test for me.

Bug: Issue 11543
Change-Id: Ie8e17770ddfebda569a8151e1b630f5a4e865c7b

qtproject/qtqa-gerrit,WANdisco/gerrit,WANdisco/gerrit,GerritCodeReview/gerrit,qtproject/qtqa-gerrit,WANdisco/gerrit,qtproject/qtqa-gerrit,GerritCodeReview/gerrit,GerritCodeReview/gerrit,GerritCodeReview/gerrit,qtproject/qtqa-gerrit,GerritCodeReview/gerrit,GerritCodeReview/gerrit,qtproject/qtqa-gerrit,qtproject/qtqa-gerrit,GerritCodeReview/gerrit,qtproject/qtqa-gerrit,WANdisco/gerrit,WANdisco/gerrit,WANdisco/gerrit,GerritCodeReview/gerrit,WANdisco/gerrit