Z3 doesn't check validity of -T option

[HuStmpHrrr]

In 4.12.4, -T:timeout can take any string for timeout, where the validity of timeout is not checked. It can be any string, and it seems if this string is not a valid number, it's simply ignored. This option should behave similarly to -t:timeout, which outputs

ERROR: Expected values for parameter timeout is an unsigned integer. It was given argument 'timeout=1000'

if given an incorrect input.