XML parsing optimizations

Traceview showed approximately 10% of total parse time inside the
synthetic 'trampoline' methods generated to provide inner classes
with access to their outer class's private fields.  The bottleneck
in this particular case is in XmlBlock and its inner class Parser.

Making the bottlneck outer-class members and methods package-scope
instead of private removes that 10% overhead being spent within
these access trampolines.

Traceview tends to overemphasize the significance of very small
methods such as these trampolines.  That said, the measured speed
gain on the ParseLargeXmlResFg op due to this patch is between
5% and 6%.

Change-Id: Ia0e3ae5408d1f9992b46e6e30dd2407090379b07