Fixed functional test in case the LS_JAVA_HOME is configured (elastic…

…#15535)

Adds filtering on Logstash output message in an integration tests when setting LS_JAVA_HOME environment variable.

qa/integration/specs/command_line_spec.rb

@@ -39,7 +39,7 @@
     execute = @logstash.run
     lines = execute.stderr_and_stdout.split("\n")
     expect(lines.shift).to match(/^(Using system java)|(Using bundled JDK)|(Using LS_JAVA_HOME defined java):/)
-    while (up_line = lines.shift).match(/OpenJDK 64-Bit Server VM warning: Option UseConcMarkSweepGC was deprecated|warning: ignoring JAVA_TOOL_OPTIONS|warning: already initialized constant Socket::Constants|.*warning: method redefined; discarding old to_int$|.*warning: method redefined; discarding old to_f$/) do end
+    while (up_line = lines.shift).match(/OpenJDK 64-Bit Server VM warning: Option UseConcMarkSweepGC was deprecated|warning: ignoring JAVA_TOOL_OPTIONS|warning: already initialized constant Socket::Constants|.*warning: method redefined; discarding old to_int$|.*warning: method redefined; discarding old to_f$|^WARNING: Logstash comes bundled with the recommended JDK.*/) do end
     expect(up_line).to match(/^Sending Logstash logs to/)
   end
 end