Update container acceptance tests with stdout/stderr changes (#17138)

In #17125 jvm setup was redirected to
stderr to avoid polluting stdout. This test was actually having to do some
additional processing to parse that information. Now that we have split the
destinations the tests can be simplified to look for the data they are trying to
validate on the appropriate stream.

qa/docker/shared_examples/container.rb

@@ -15,16 +15,13 @@
 
     it 'should run with the correct version' do
       console_out = exec_in_container(@container, 'logstash --version')
-      console_filtered = console_out.split("\n")
-            .delete_if do |line|
-              line =~ /Using LS_JAVA_HOME defined java|Using system java: /
-            end.join
-      expect(console_filtered).to match /#{version}/
+      expect(console_out).to match /#{version}/
     end
 
     it 'should run with the bundled JDK' do
-      first_console_line = exec_in_container(@container, 'logstash --version').split("\n")[0]
-      expect(first_console_line).to match /Using bundled JDK: \/usr\/share\/logstash\/jdk/
+      full_command = exec_in_container_full(@container, 'logstash --version')
+      std_err = full_command[:stderr].join.chomp.strip
+      expect(std_err).to match /Using bundled JDK: \/usr\/share\/logstash\/jdk/
     end
 
     it 'should be running an API server on port 9600' do