8076543: Add @modules as needed to the langtools tests
Reviewed-by: jjg, shurailine

8038730: Clean up the way JavadocTester is invoked, and checks for errors.
Reviewed-by: ksrini, sogoel, bpatel

8040903: Clean up use of BUG_ID in javadoc tests
Reviewed-by: ksrini

8031649: Clean up javadoc tests
Reviewed-by: jjg
Contributed-by: neil.toda@oracle.com

8007610: javadoc doclint does not work with -private
Reviewed-by: darcy

6735320: StringIndexOutOfBoundsException for empty @serialField tag
Reviewed-by: jjg, bpatel