[BCEL] Not breaking BC for 6.3

[Gary Gregory]

Hi All,

WRT:

[ERROR] 7012: org.apache.bcel.classfile.Visitor: Method 'public void
visitConstantDynamic(org.apache.bcel.classfile.ConstantDynamic)' has been
added to an interface

IMO, the simplest way for BC 6.3 to avoid breaking binary compatibility is
to update from Java 7 to 8 and make the new method:

org.apache.bcel.classfile.Visitor.visitConstantInterfaceMethodref(ConstantInterfaceMethodref)

be a Java 8 default method.

Gary