CRASH opcodes sample running url_unittests

Running without --single-process-tests seems to crash about 1 in every 5 runs:

```
# bin32/drrun -c api/bin/libopcodes.so -- ~/chromium/out_arm/Release/url_unittests
Client opcodes is running
IMPORTANT DEBUGGING NOTE: batches of tests are run inside their
own process. For debugging a test inside a debugger, use the
--gtest_filter= flag along with
--single-process-tests.
Using sharding settings from environment. This is shard 0/1
Using 8 parallel jobs.

Failed to get out-of-band test success data, dumping full stdio below:

[1/76] GURLTest.Resolve (UNKNOWN)
```

But I can't reproduce it easily, have to run in a loop:

```

<-- parent 11155 forked child 11181 -->
<-- parent 11155 forked child 11184 -->
<(1+x) Handling our fault in a TRY at 0x711fc8f4>


<-- parent 11155 forked child 11212 -->
```