Revert "ElasticContainer: Limit heap usage for test containers"

Limiting the heap causes severe performance degradation and
intermittent test failures when running all the tests at once.

This was not noticed before because only a subset of tests were
executed.

Rather than attempting to find a value that works, just revert
the limitation.

This reverts commit d332be11ab.

Change-Id: I8851025d14814aad4b03a917b548452fd4584a5f

gerrit-elasticsearch/src/main/java/com/google/gerrit/elasticsearch/testing/ElasticContainer.java

@@ -30,7 +30,6 @@ public class ElasticContainer<SELF extends ElasticContainer<SELF>> extends Gener
     // See https://github.com/testcontainers/testcontainers-java/issues/343
     try {
       ElasticContainer<?> container = new ElasticContainer<>(version);
-      container.addEnv("ES_JAVA_OPTS", "-Xms128m -Xmx128m");
       container.start();
       return container;
     } catch (Throwable t) {