Remove calls to Statement.getUpdateCount

[SylvainJuge]

Due to many issues and unexpected side-effects of calling Statement.getUpdateCount, we decided to remove calls to this method performed by our agent.

This will partially revert work that has been done for elastic/apm#112 / #707

Here is the non-exhaustive list of issues/PR that are related to this simple (but cursed) feature:

• Fix JDBC non-supported getUpdateCount #1008 getUpdateCount is not supported by all drivers and might throw SQLException
• Catch SQLException when calling JDBC API from agent #1035 Improvement on Fix JDBC non-supported getUpdateCount #1008 to avoid excessive logging
• Avoid side-effects of calling Statement.getUpdateCount #1139 Attempt to avoid side effects of non-idempotent implementations (like Oracle).

This will be a two-step process

• quickly remove calls to getUpdateCount from the agent
• properly proceed to removal, and make sure that feature is still supported for Statement.executeUpdate(), for which we can capture the return value.