fix($compile): removing unnecessary white space in element-transclusion comments

Fixes #14549

Closes #14550

Author: ivomju

src/ng/compile.js

@@ -1621,7 +1621,8 @@ function $CompileProvider($provide, $$sanitizeUriProvider) {
     compile.$$createComment = function(directiveName, comment) {
       var content = '';
       if (debugInfoEnabled) {
-        content = ' ' + (directiveName || '') + ': ' + (comment || '') + ' ';
+        content = ' ' + (directiveName || '') + ': ';
+        if (comment) content += comment + ' ';
       }
       return window.document.createComment(content);
     };

test/ng/compileSpec.js

@@ -8407,7 +8407,7 @@ describe('$compile', function() {
           expect(function() {
             $compile('<div first second></div>');
           }).toThrowMinErr('$compile', 'multidir', 'Multiple directives [first, second] asking for transclusion on: ' +
-                  '<!-- first:  -->');
+                  '<!-- first: -->');
         });
       });