canonicalPath Refactor

HttpURI throws IAE rather than BME

jetty-http/src/main/java/org/eclipse/jetty/http/HttpURI.java

@@ -744,7 +744,7 @@ else if (_path != null)
             String decodeNonCanonical = URIUtil.decodePath(_path);
             _decodedPath = URIUtil.canonicalPath(decodeNonCanonical);
             if (_decodedPath == null)
-                throw new BadMessageException("Bad URI");
+                throw new IllegalArgumentException("Bad URI");
         }
     }