There is an convention in many of the javadoc tests to name the output directory for the javadoc run after the bug number being fixed, using a String named BUG_ID.

The convention is unnecessary and misleading. jtreg already keeps the output for each test separate.

We should
1. Remove declarations of BUG_ID from the tests using this convention
2. Replace use of BUG_ID with a new variable OUTDIR
3. Add a shared declaration of OUTDIR to JavadocTester class