Optimize jastow constants for javax->jakarta transformation

Tools like the Eclipse Transformer have a facility for transformation of constant text in class files. But they currently work by directly matching constant value text to keys in a provided map input/output values. (See https://github.com/eclipse/transformer/issues/79). Jastow should ease creation of such a map by separating text needing transformation from the rest of a constant value that does not need it.

E.g. from the Generator class:

out.printil("private void _jspInit(javax.servlet.ServletConfig config) {");

That can become 3 lines so "javax.servlet.ServletConfig" can be the key in the transformation rules instead of the entire string.