drcacheoff.fork test failing with non-det output on AArch64

http://139.178.82.61:8080/job/DynamoRIO-AArch64-Precommit/2926/consoleFull

Looks like it's just the order of "parent waiting" and "child is running"

```
221: CMake Error at /var/lib/jenkins/workspace/DynamoRIO-AArch64-Precommit/suite/tests/runmulti.cmake:132 (message):
221: output |parent is running under DynamoRIO
221:
221: child is running under DynamoRIO
221:
221: parent waiting for child
221:
221: child has exited
221:
221: Cache simulation results:
221:
221: Core #0 (1 thread(s))
221:
221: L1I stats:
221: Hits: 182458
221: Misses: 1128
221: Compulsory misses: 1107
221: Invalidations: 0
221: Miss rate: 0.61%
221: L1D stats:
221: Hits: 52416
221: Misses: 1972
221: Compulsory misses: 2827
221: Invalidations: 0
221: Prefetch hits: 249
221: Prefetch misses: 1743
221: Miss rate: 3.63%
221:
221: Core #1 (0 thread(s))
221:
221: Core #2 (0 thread(s))
221:
221: Core #3 (0 thread(s))
221:
221: LL stats:
221:
221: Hits: 529
221: Misses: 2571
221: Compulsory misses: 3930
221: Invalidations: 0
221: Prefetch hits: 384
221: Prefetch misses: 1359
221: Local miss rate: 82.94%
221: Child hits: 235123
221: Total miss rate: 1.08%
221:
221: | failed to match expected output |parent is running under DynamoRIO
221:
221: parent waiting for child
221:
221: child is running under DynamoRIO
221:
221: child has exited
221:
221: Cache simulation results:
221:
221: Core #0 \(1 thread\(s\)\)
221:
221: L1I stats:
221: Hits: *[0-9,\.]*
221: Misses: *[0-9,\.]*
221: Compulsory misses: *[0-9,\.]*
221: Invalidations: *0
221:
221: .* Miss rate: [0-3][,\.]..%
221:
221: L1D stats:
221: Hits: *[0-9,\.]*
221: Misses: *[0-9,\.]*
221: Compulsory misses: *[0-9,\.]*
221: Invalidations: *0
221:
221: .* Miss rate: [0-9][,\.]..%
221:
221: Core #1 \(0 thread\(s\)\)
221:
221: Core #2 \(0 thread\(s\)\)
221:
221: Core #3 \(0 thread\(s\)\)
221:
221: LL stats:
221:
221: Hits: *[0-9,\.]*
221: Misses: *[0-9,\.]*
221: Compulsory misses: *[0-9,\.]*
221: Invalidations: *0
221:
221: .* Local miss rate: *[0-9,.]*%
221:
221: Child hits: *[0-9,\.]*
221: Total miss rate: [0-4][,\.]..%
221:
221: |
221:
221:
276/328 Test #221: code_api|tool.drcacheoff.fork ...................................***Failed 1.42 sec
```