Fix testMultipleConditions flake

Use vector<int> instead of vector<bool>.
vector<bool> is not thread-safe:
https://en.cppreference.com/w/cpp/container#Thread_safety

Fixes: 156690351
Test: atest --iterations=500
statsd_test:MultiConditionTrigger#TestMultipleConditions

Change-Id: I9121747ffbee0864afbff993e7fe417104827952