Removed external URL test dependency

Would cause test failures if no network was available during test execution. Since it was authored, the buffer variants that tripped the original bug have had better coverage added, no it is no longer required.

Fixes #1733
Closes #1754

src/test/java/org/jsoup/integration/ConnectTest.java

@@ -517,15 +517,12 @@ public void canFetchBinaryAsBytes() throws IOException {
     @Test
     public void handlesUnknownEscapesAcrossBuffer() throws IOException {
         String localPath = "/htmltests/escapes-across-buffer.html";
-        String url =
-            "https://gist.githubusercontent.com/krystiangorecki/d3bad50ef5615f06b077438607423533/raw/71adfdf81121282ea936510ed6cfe440adeb2d83/JsoupIssue1218.html";
         String localUrl = FileServlet.urlTo(localPath);
 
-        Document docFromGithub = Jsoup.connect(url).get(); // different chunks meant GH would error but local not...
         Document docFromLocalServer = Jsoup.connect(localUrl).get();
         Document docFromFileRead = Jsoup.parse(ParseTest.getFile(localPath), "UTF-8");
 
-        String text = docFromGithub.body().text();
+        String text = docFromLocalServer.body().text();
         assertEquals(14766, text.length());
         assertEquals(text, docFromLocalServer.body().text());
         assertEquals(text, docFromFileRead.body().text());