Add the benchmark of XmlBlock for CriticalNative

In order to make sure that CriticalNative is better than "FastNaive",
this patch adds android.content.res.XmlBlockBenchmark to measure the
current performance of FastNaive.

Bug: 173709508
Test: atest \
    CorePerfTests:android.content.res.XmlBlockBenchmark
Change-Id: Iafa1e043425353bf430832ee5edd38947e667404