Fix crash with too large clipboard data

If too much text is copied in the session, String.fromCharCode.apply()
would crash in Safari on macOS and Chrome on Linux. This commit fixes
this issue by avoiding apply() altogether. Also added test to cover this
issue.

core/rfb.js

@@ -1504,7 +1504,11 @@ export default class RFB extends EventTargetMixin {
                 streamInflator.setInput(null);
 
                 if (textData !== null) {
-                    textData = String.fromCharCode.apply(null, textData);
+                    let tmpText = "";
+                    for (let i = 0; i < textData.length; i++) {
+                        tmpText += String.fromCharCode(textData[i]);
+                    }
+                    textData = tmpText;
 
                     textData = decodeUTF8(textData);
                     if ((textData.length > 0) && "\0" === textData.charAt(textData.length - 1)) {