[NO ISSUE] Handle Accept-Charset in QueryResultApiServlet

- exercise non-UTF8 Accept-Charset in TestExecutor
- remove double-buffering on http responses
- minor refactoring / cleanup

Change-Id: I8f37eb684bf2457e5ff451bf5c8fbca742d531f2
Reviewed-on: https://asterix-gerrit.ics.uci.edu/3191
Reviewed-by: Murtadha Hubail <mhubail@apache.org>
Sonar-Qube: Jenkins <jenkins@fulliautomatix.ics.uci.edu>
Tested-by: Michael Blow <mblow@apache.org>
diff --git a/hyracks-fullstack/hyracks/hyracks-http/pom.xml b/hyracks-fullstack/hyracks/hyracks-http/pom.xml
index a67fa15..46e2004 100644
--- a/hyracks-fullstack/hyracks/hyracks-http/pom.xml
+++ b/hyracks-fullstack/hyracks/hyracks-http/pom.xml
@@ -95,5 +95,11 @@
       <type>test-jar</type>
       <scope>test</scope>
     </dependency>
+    <dependency>
+      <groupId>org.apache.hyracks</groupId>
+      <artifactId>hyracks-test-support</artifactId>
+      <version>${project.version}</version>
+      <scope>test</scope>
+    </dependency>
   </dependencies>
 </project>
\ No newline at end of file