TUN-2279: Revert path encoding fix

This reverts commit f6c7f8a96c.

streamhandler/request.go

@@ -45,13 +45,16 @@ func H2RequestHeadersToH1Request(h2 []h2mux.Header, h1 *http.Request) error {
 			// Otherwise the host header will be based on the origin URL
 			h1.Host = header.Value
 		case ":path":
-			// Separate the path and the (optional) query from each other
-			chunks := strings.SplitN(header.Value, "?", 2)
-
-			h1.URL.Path = chunks[0]
-			if len(chunks) > 1 {
-				h1.URL.RawQuery = chunks[1]
+			u, err := url.Parse(header.Value)
+			if err != nil {
+				return fmt.Errorf("unparseable path")
 			}
+			resolved := h1.URL.ResolveReference(u)
+			// prevent escaping base URL
+			if !strings.HasPrefix(resolved.String(), h1.URL.String()) {
+				return fmt.Errorf("invalid path")
+			}
+			h1.URL = resolved
 		case "content-length":
 			contentLength, err := strconv.ParseInt(header.Value, 10, 64)
 			if err != nil {