fix #951 Enable back test.aria.templates.keyboardNavigation.TableNavTestCase on IE <= 8

This commit is a new fix for the issue that commit 8fcb1826e247320e3730a19e9736b2ecee12c148
tried to solve, and which was reverted in commit 82b8cbf1ea1682361fac60ccef35d558c6aa6bba.