RFR(jdk10/jaxp) 8163121: BCEL: update to the latest 6.0 release

[huizhe wang]

Please review an update to BCEL release 6.0 [1].

The sources are basically that from the release bundle with the 
following exceptions:

  * Classes that were not included in the original version are excluded;
  * Classes that are deprecated in BCEL 6.0 are removed;
  * Classes that are used only for the above classes are also removed;
  * Many fields were deprecated in BCEL 6.0 in order to discourage
    direct references, in the JDK, I've removed such deprecation and
    instead made them private/final.
  * BCEL 6.0 applied 'final' to global/local variables pretty
    extensively, which were the only changes to many of the classes.
  * A few Transform classes were updated to adopt to BCEL 6.0.
  * JDK-8162527 [JAXP] XSLT: Investigate why bumping the default class
    file version to 49 (Java 5.0) or higher for bytecode generation
    doesn't work [2] has not been resolved as of this update. Additional
    change [3] is needed before we can move up to possibly Java 5.0.


BCEL has been a very old component. This update therefore removed a 
large amount of warnings (900+), which is very helpful to the cleaning 
effort.

All tests passed, including the JCK.

JBS: https://bugs.openjdk.java.net/browse/JDK-8163121
webrevs: http://cr.openjdk.java.net/~joehw/jdk10/8163121/webrev/


[1] https://archive.apache.org/dist/commons/bcel/RELEASE-NOTES.txt
[2] https://bugs.openjdk.java.net/browse/JDK-8162527
[3] https://bugs.openjdk.java.net/browse/JDK-8185991

Thanks,
Joe