Standard sample target on 'runtest' where only one appropriate target exists

Currently most of the quickstarts and esb samples use 'sendhello' as the target for invoking the test. There are also other variations, such as sendmesg, etc.

These should be standardised on 'runtest' to match the esb samples convention.

Where there are multiple invocation targets, such as with the simple_correlation's sendhello and sendgoodbye, then these should be left as they are.