asan: fix a windows test

Before commit "sanitizer_common: introduce kInvalidTid/kMainTid"
asan invalid/unknown thread id was 0xffffff, so presumably we printed "T16777215".
Now it's -1, so we print T-1. Fix the test.
I think the new format is even better, "T-1" clearly looks like something special
rather than a random large number.

Reviewed By: vitalybuka

Differential Revision: https://reviews.llvm.org/D101634