Apple's certification was expired so Xcode 10.2.1 package needs to be
updated from the Apple's download server. Old one causing problems with
RTA tests.
Task-number: QTQAINFRA-3317
Change-Id: I5006f95ab420e26523d2621800d80322a52bb9a2
Reviewed-by: Tony Sarajärvi <tony.sarajarvi@qt.io>