Disable P2pPartitionedPutLongBenchmark (#140)

- This benchmark is unstable and does not produce reliable results. See
GEODE-8950 for further details.

Authored-by: Donal Evans <doevans@vmware.com>

geode-benchmarks/build.gradle

@@ -86,6 +86,7 @@ task benchmark(type: Test) {
   testLogging { exceptionFormat = 'full' }
 
   exclude "**/NoopBenchmark.class"
+  exclude "**/P2pPartitionedPutLongBenchmark.class"
 
   forkEvery 1
   failFast = true