RFR (JDK13/java.xml) 8224157: BCEL: update to version 6.3.1

[Joe Wang]

Please review an update to BCEL 6.3.1. This changeset will go into JDK13 
if approved, 14 if not.

1. Format
     The changeset looks big, the majority of the changes however were 
only different in format (i.e. Const.java). Unlike previous updates, I'm 
leaving the format as they are in the upstream source so that they won't 
show up in future updates. The only change I made were those that had 
extremely long lines.

2. Exclusions
     Since the BCEL component is for xml transform only, several 
classes, that were not in the JDK, were excluded. Among them, 
JavaWrapper.java for example can be problematic as it may use an 
user-specified classloader to load arbitrary classes. It and related 
classes were therefore excluded.

3. Warnings
     Warnings were the main reason for the changes made to the original 
source. It has been done in the previous update. For this update 
therefore, I only had to re-apply them after making copies of the 
upstream source. Still, I updated the LastModified field to indicate a 
modification to the original source.

4. Deprecated fields to private
     Deprecated fields in the original source were changed to private 
ones in previous update. The changes are inherited in this update. 
Again, the LastModified fields are also updated.

5. Test
     Since the update does not affect the usage of the BCEL component, 
it is essential to pass all of the existing tests. I've run the tests 
multiple times and noted that all of the XML functional and unit tests 
passed, so were JCK XML tests. I've also done a comparison between 
builds before and after applying the BCEL update, and found no change in 
performance.

JBS: https://bugs.openjdk.java.net/browse/JDK-8224157
webrevs: http://cr.openjdk.java.net/~joehw/jdk13/8224157/webrev/

Thanks,
Joe