tool.drcachesim.coherence timeout on AppVeyor.

[hgreving2304]

See https://ci.appveyor.com/project/DynamoRIO/dynamorio/builds/27051924

257/257 Test #213: code_api|tool.drcachesim.coherence ...........................***Timeout 150.01 sec

[derekbruening]

Is this some kind of hang in drcachesim? That would be bad: it could be in the tracer?
That would be high priority.

How long does this test normally take?
I see ~80s in the prior run: https://ci.appveyor.com/project/DynamoRIO/dynamorio/builds/27050810?fullLog=true
So it is slow.

But looking at the timeout log in more detail:

[00:11:04] 213:      Total Number Of iterations   :  10
[00:11:04] 213:     ...................................................................
[00:11:04] 213: Assertion failed: type_is_instr(cur_ref.instr.type), file ..\..\clients\drcachesim\reader\reader.cpp, line 132
[00:12:05] 257/257 Test #213: code_api|tool.drcachesim.coherence ...........................***Timeout 150.01 sec

It looks to me like this is #3320 and it hit the time limit before the process exited (a full minute later though: maybe some issue reporting the assert -- in any case it does not look like a new bug).