Remove duplicate error

Prior to this change, if an element can't be found, two error messages are
logged.  This change removes one of those two.

Testing done:

Ran script with missing element.
Modify message in findElement

This change removes duplicate text when finding an element solely by index.

Testing done:

Ran script with and without finding solely by index.
Update unsupported JRE/JDK warning

It's been some time since Oracle absorbed Sun and they've long since updated
java.vendor to reflect that.  This change now only issues the unsupported
vendor warning if it's neither Sun nor Oracle.

Testing done:

Ran VDD, didn't see the warning.