Fix CTS uaccess tagging tests.

Due to a bad merge we ended up testing for uaccess failure in async
mode rather than sync mode. Fix it by moving the assert to the correct
function. The uaccess is expected to succeed in async mode, so test
for that.

Bug: 135772972
Change-Id: I40259274fa5a78d3e5d266b6589485e659f8f8eb
1 file changed