can't run caliper benchmarks on the host dalvikvm

```
it's a good job x86 has performance to burn, because i'm unable to test the
effect of any of my changes...

~/local-disk/dd5$ vogar --mode host --benchmark
~/Projects/dalvik/benchmarks/regression/ByteBufferBenchmark.java --
--warmupMillis 100 --runMillis 100 -DbufferType=DIRECT -Daligned=true
/home/enh/Projects/vogar/bin/../build/vogar.jar
Actions: 1
Action benchmarks.regression.ByteBufferBenchmark
0% Scenario{vm=dalvikvm, benchmark=ByteBuffer_getByte, aligned=true, bufferType=DIRECT, byteOrder=BIG}com.google.caliper.UserException$ExceptionFromUserCodeException: An exception was thrown from the benchmark code.
at com.google.caliper.Runner.runOutOfProcess(Runner.java:364)
at com.google.caliper.Runner.run(Runner.java:82)
at vogar.target.CaliperRunner.run(CaliperRunner.java:42)
at vogar.target.TestRunner.run(TestRunner.java:247)
at vogar.target.TestRunner.run(TestRunner.java:121)
at vogar.target.TestRunner.main(TestRunner.java:258)
at dalvik.system.NativeStart.main(Native Method)
Caused by: java.lang.RuntimeException: failed to clear log
at com.google.caliper.DalvikVm.init(DalvikVm.java:56)
at com.google.caliper.Runner.measure(Runner.java:244)
at com.google.caliper.Runner.runScenario(Runner.java:201)
at com.google.caliper.Runner.runOutOfProcess(Runner.java:353)
... 6 more
Caused by: java.io.IOException: Error running exec(). Command: [logcat, -c] Working Directory: null Environment: [...]
at java.lang.ProcessManager.exec(ProcessManager.java:224)
at java.lang.ProcessBuilder.start(ProcessBuilder.java:202)
at com.google.caliper.DalvikVm.init(DalvikVm.java:54)
... 9 more
Caused by: java.io.IOException: No such file or directory
at java.lang.ProcessManager.exec(Native Method)
at java.lang.ProcessManager.exec(ProcessManager.java:222)
... 11 more

benchmarks.regression.ByteBufferBenchmark OK (SUCCESS)
Outcomes: 1. All successful. Took 4.12 s.
~/local-disk/dd5$

```

Original issue reported on code.google.com by `e...@google.com` on 12 Sep 2010 at 10:28