[jdk13u-dev] RFR: 8235368: Update BCEL to Version 6.4.1

[Dmitry Cherepanov]

8235368: Update BCEL to Version 6.4.1

Applies cleanly except @LastModified timestamps in two files below (due to JDK-8248348 with newer timestamps is already included in 13u)

src/java.xml/share/classes/com/sun/org/apache/bcel/internal/generic/BranchInstruction.java
src/java.xml/share/classes/com/sun/org/apache/bcel/internal/generic/Instruction.java

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Commit messages:
 - Backport e8f8eef9087c2be14bb1726cf9892517581067cd

Changes: https://git.openjdk.java.net/jdk13u-dev/pull/227/files
 Webrev: https://webrevs.openjdk.java.net/?repo=jdk13u-dev&pr=227&range=00
  Issue: https://bugs.openjdk.java.net/browse/JDK-8235368
  Stats: 3402 lines in 318 files changed: 2175 ins; 527 del; 700 mod
  Patch: https://git.openjdk.java.net/jdk13u-dev/pull/227.diff
  Fetch: git fetch https://git.openjdk.java.net/jdk13u-dev pull/227/head:pull/227

PR: https://git.openjdk.java.net/jdk13u-dev/pull/227