During the new Handler deadlock tests, a test formatter is called with a log record for which the parameter array could be null. This is not checked for and an attempt is made to iterate the contents, causing a null pointer exception.

It is not 100% clear if this error is a rare race condition which breaks an otherwise passing test, or something which happens in response to a timeout, but either way the test should be robust against it (the test is only rarely failing due to this, so debug information is not yet available).

The fix is to simple add a null check and skip an attempt to iterate the parameter array.