Improve class loading speed

Classes are loaded into individual class pools instead of the default
class pool. This increases class loading speed by up ~640%.

Author: dustinbyrne

src/main/java/com/appland/appmap/transform/ClassFileTransformer.java

@@ -142,7 +142,7 @@ public byte[] transform(ClassLoader loader,
                           Class redefiningClass,
                           ProtectionDomain domain,
                           byte[] bytes) throws IllegalClassFormatException {
-    ClassPool classPool = ClassPool.getDefault();
+    ClassPool classPool = new ClassPool(true);
     classPool.appendClassPath(new LoaderClassPath(loader));
 
     try {