[TEST] fix RHLC "testDefaultNamedXContents" failure after x-pack aggregations removal

[tlfeng]

Issue #, if available:

After X-pack Aggregations removed from RHLC in PR #59,
There is a few lines of test needs to be removed as well, those lines were orignally added by commit: 2dac36d 146def8 c5443f7

> Task :client:rest-high-level:test

REPRODUCE WITH: ./gradlew ':client:rest-high-level:test' --tests "org.elasticsearch.client.RestHighLevelClientTests.testDefaultNamedXContents" -Dtests.seed=AB9997A3B2546BC7 -Dtests.security.manager=true -Dtests.locale=tr -Dtests.timezone=America/Cayenne -Druntime.java=15

org.elasticsearch.client.RestHighLevelClientTests > testDefaultNamedXContents FAILED
java.lang.AssertionError
at __randomizedtesting.SeedInfo.seed([AB9997A3B2546BC7:6EA7DF105289DEF2]:0)
at org.junit.Assert.fail(Assert.java:86)
at org.junit.Assert.assertTrue(Assert.java:41)
at org.junit.Assert.assertTrue(Assert.java:52)
at org.elasticsearch.client.RestHighLevelClientTests.testDefaultNamedXContents(RestHighLevelClientTests.java:644)

Description of changes:

• Remove lines of test for X-pack Aggregations in RestHighLevelClientTests
• Remove one blank line added by PR Remove x-pack aggregations hlrc. #59

Testing:

$ ./gradlew ':client:rest-high-level:test' --tests "org.elasticsearch.client.RestHighLevelClientTests.testDefaultNamedXContents"
=======================================
Elasticsearch Build Hamster says Hello!
  Gradle Version        : 6.6.1
  OS Info               : Linux 5.4.0-1037-aws (amd64)
  JDK Version           : 14 (JDK)
  JAVA_HOME             : /usr/lib/jvm/java-14-openjdk-amd64
  Random Testing Seed   : C179C3003E841286
  In FIPS 140 mode      : false
=======================================

> Task :client:rest-high-level:compileTestJava
Note: /home/ftianli/github/search/client/rest-high-level/src/test/java/org/elasticsearch/client/RestHighLevelClientTests.java uses or overrides a deprecated API.
Note: Recompile with -Xlint:deprecation for details.

> Task :client:rest-high-level:test
WARNING: Illegal reflective access by org.mockito.cglib.core.ReflectUtils$2 (file:/home/ftianli/.gradle/caches/modules-2/files-2.1/org.elasticsearch/securemock/1.2/98201d4ad5ac93f6b415ae9172d52b5e7cda490e/securemock-1.2.jar) to method java.lang.ClassLoader.defineClass(java.lang.String,byte[],int,int,java.security.ProtectionDomain)

BUILD SUCCESSFUL in 4s
50 actionable tasks: 2 executed, 48 up-to-date

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[tlfeng]

Closed as it's duplicate with PR # 65