Collapse verbose .execute().actionGet() calls in tests (#102502)

Cleaning this up a little even though it's still quite horrible.
`.get()` in this API actually means `actionGet()` so to speak.
I think a good first step to cleaning this up is to at least reduce
the duplication though and save 1k lines.

modules/lang-expression/src/internalClusterTest/java/org/elasticsearch/script/expression/MoreExpressionIT.java

@@ -650,8 +650,7 @@ public class MoreExpressionIT extends ESIntegTestCase {
                     .endObject()
                     .endObject()
             )
-            .execute()
-            .actionGet();
+            .get();
         refresh();
         // access .lat
         assertNoFailuresAndResponse(buildRequest("doc['location'].lat"), rsp -> {