Core: Delete outdated onerror handler

code/lib/core-common/templates/base-preview-head.html

@@ -326,24 +326,4 @@
     // eslint-disable-next-line no-console
     console.warn('unable to connect to top frame for connecting dev tools');
   }
-
-  window.onerror = function onerror(message, source, line, column, err) {
-    if (window.CONFIG_TYPE !== 'DEVELOPMENT') return;
-    // eslint-disable-next-line no-var, vars-on-top
-    var xhr = new window.XMLHttpRequest();
-    xhr.open('POST', '/runtime-error');
-    xhr.setRequestHeader('Content-Type', 'application/json;charset=UTF-8');
-    xhr.send(
-      JSON.stringify({
-        /* eslint-disable object-shorthand */
-        message: message,
-        source: source,
-        line: line,
-        column: column,
-        error: err && { message: err.message, name: err.name, stack: err.stack },
-        origin: 'preview',
-        /* eslint-enable object-shorthand */
-      })
-    );
-  };
 </script>