JooqLogger log methods don't check if log level is enabled

[lukaseder]

The various JooqLogger.trace(), debug(), info(), warn(), error() methods don't re-check if the log level is enabled. They rely on the logging backend to do this correctly. But there can be other reasons why the logger is disabled, including:

• Someone turned it off using reflection
• Add support for generic org.jooq.log.<logger>=threshold system properties #15050 (a new system property)

The globalThreshold is already verified. So, this bug doesn't really affect a lot of users, except those who use reflection. It became apparent only when implementing #15050. Thus, there's no need for a backport.

[lukaseder]

Implemented in jOOQ 3.19.0. As the driving reason for this fix (#15050) won't be backported, this fix also won't be backported.