Allow sampler timeout on all Samplers (including SMTP)

**orimarko** ([Bug 61819](https://bz.apache.org/bugzilla//show_bug.cgi?id=61819&redirect=false)):
Sample Timeout is a useful tool for preventing "stuck" request that pauses the test, but it seems that it isn't fully supported:

For this to work, the sampler must implement Interruptible. The following samplers are known to do so:

AJP, BeanShell, FTP, HTTP, Soap, AccessLog, MailReader, JMS Subscriber, TCPSampler, TestAction, JavaSampler

For example SmtpSampler can't be interrupted with Sample Timeout

OS: All