WFLY-3934 TimerServiceImpl should use message patterns

When running an allocation profile on our WildFly AS instance debug
logging in `TimerServiceImpl` showed up. The problem is that
`TimerServiceImpl` unconditionally generates debug strings using string
concatenation.

 * use `#debugv` instead of `#debug` for debug messages that take
   arguments to avoid allocating strings in case when debug logging is
   disabled
 * put calls to `#getTimedObjectId` for debug strings in `if` blocks
   since it additionally allocates strings

Issue: WFLY-3934
https://issues.jboss.org/browse/WFLY-3934