InlineEdit: Switch to using native jump-to-line addon

The feature request to add native jump-to-line dialog to CodeMirror: [1]
was solved in context of this PR: [2]. So that now we can switch from
native and ugly Window#prompt() to nice looking CodeMirror addon.

Test Plan:

- Open change editor
- Type Alt-G|Ctrl-L|Cmd-L
- Jump to line dialog appears
- Type the line number: 42 and hit enter
- Confirm that the cursor is jumped to line 42

[1] https://github.com/codemirror/CodeMirror/issues/3030
[2] https://github.com/codemirror/CodeMirror/pull/3682

Change-Id: Ic9b889ea1efe26b3a19c5e885f1668009acc12ad

gerrit-gwtui/src/main/java/com/google/gerrit/client/editor/EditScreen.java

@@ -257,20 +257,7 @@ public class EditScreen extends Screen {
     return new Runnable() {
       @Override
       public void run() {
-        String n = Window.prompt(EditConstants.I.gotoLineNumber(), "");
-        if (n != null) {
-          try {
-            int line = Integer.parseInt(n);
-            line--;
-            if (line >= 0) {
-              cm.scrollToLine(line);
-            }
-          } catch (NumberFormatException e) {
-            // ignore non valid numbers
-            // We don't want to popup another ugly dialog just to say
-            // "The number you've provided is invalid, try again"
-          }
-        }
+        cm.execCommand("jumpToLine");
       }
     };
   }

lib/codemirror/cm.defs

@@ -19,6 +19,7 @@ CM_ADDONS = [
   'edit/trailingspace.js',
   'scroll/annotatescrollbar.js',
   'scroll/simplescrollbars.js',
+  'search/jump-to-line.js',
   'search/matchesonscrollbar.js',
   'search/searchcursor.js',
   'search/search.js',