Cherry pick some recent lexbor changes

The following changes are cherry-picked:
- c60846689d core/str.c: Fix undefined behavior in function lexbor_str_append
- 92260fd670 URL: fixed hostname setter if port is specified.

ext/lexbor/lexbor/core/str.c

@@ -133,6 +133,10 @@ lexbor_str_append(lexbor_str_t *str, lexbor_mraw_t *mraw,
 {
     lxb_char_t *data_begin;
 
+	if (length == 0) {
+		return str->data;
+	}
+
     lexbor_str_check_size_arg_m(str, lexbor_str_size(str),
                                 mraw, (length + 1), NULL);
 

ext/lexbor/lexbor/url/url.c

@@ -1818,7 +1818,7 @@ again:
                     }
 
                     if (override_state == LXB_URL_STATE_HOSTNAME_STATE) {
-                        lxb_url_parse_return(orig_data, buf, LXB_STATUS_OK);
+                        lxb_url_parse_return(orig_data, buf, LXB_STATUS_ERROR);
                     }
 
                     status = lxb_url_host_parse(parser, begin, p, &url->host,

ext/uri/tests/026.phpt

@@ -8,21 +8,27 @@ uri
 $url1 = Uri\WhatWg\Url::parse("https://example.com");
 $url2 = $url1->withHost("test.com");
 $url3 = $url2->withHost("t%65st.com"); // test.com
-$url4 = $url3->withHost("test.com:8080");
-
-var_dump($url1->getAsciiHost());
-var_dump($url2->getAsciiHost());
-var_dump($url3->getAsciiHost());
-var_dump($url4->getAsciiHost());
-var_dump($url4->getPort());
-
 try {
-    $url4->withHost("t%3As%2Ft.com"); // t:s/t.com
+    $url3->withHost("test.com:8080");
 } catch (Uri\WhatWg\InvalidUrlException $e) {
     echo $e->getMessage() . "\n";
 }
 
-var_dump($url4->withHost("t:s/t.com"));
+var_dump($url1->getAsciiHost());
+var_dump($url2->getAsciiHost());
+var_dump($url3->getAsciiHost());
+
+try {
+    $url3->withHost("t%3As%2Ft.com"); // t:s/t.com
+} catch (Uri\WhatWg\InvalidUrlException $e) {
+    echo $e->getMessage() . "\n";
+}
+
+try {
+    $url3->withHost("t:s/t.com");     // t:s/t.com
+} catch (Uri\WhatWg\InvalidUrlException $e) {
+    echo $e->getMessage() . "\n";
+}
 
 try {
     $url2->withHost(null);
@@ -38,30 +44,12 @@ var_dump($url2->getAsciiHost());
 
 ?>
 --EXPECTF--
+The specified host is malformed
 string(11) "example.com"
 string(8) "test.com"
 string(8) "test.com"
-string(8) "test.com"
-NULL
 The specified host is malformed (DomainInvalidCodePoint)
-object(Uri\WhatWg\Url)#%d (%d) {
+The specified host is malformed
-  ["scheme"]=>
-  string(5) "https"
-  ["username"]=>
-  NULL
-  ["password"]=>
-  NULL
-  ["host"]=>
-  string(8) "test.com"
-  ["port"]=>
-  NULL
-  ["path"]=>
-  string(1) "/"
-  ["query"]=>
-  NULL
-  ["fragment"]=>
-  NULL
-}
 The specified host is malformed (HostMissing)
 string(7) "foo.com"
 string(8) "test.com"