t/run/exit.t: Fix syntax of 'my'

[khwilliamson]

I found this by code reading

• This set of changes does not require a perldelta entry.

[jkeenan]

AFAICT this is only a bug if we are not running under use strict;. However, if we attempt to use strict;, this is not the first compilation error we get.

$ ./perl -Ilib -c t/run/exit.t
t/run/exit.t syntax OK

$ ./perl -Ilib -Mstrict -c t/run/exit.t
Global symbol "$numtests" requires explicit package name (did you forget to declare "my $numtests"?) at t/run/exit.t line 19.
BEGIN not safe after errors--compilation aborted at t/run/exit.t line 20.

Even if we fix the code at line 19, there are two other places where compilation fails before we get to the statement you have identified. So I think this should be characterized as sub-optimal coding rather than a bug per se.

Does something different happen on zOS?

[khwilliamson]

I wrote that commit a while ago; without a message. I think I just noticed the weirdness by looking through it.