New allocation profiler

[Vladimir Sitnikov]

> So (puts his Maintainer Hat on), please fold HotspotAllocationProfiler
> into GCProfiler, if don't have strong objections against doing so.

Will do that.

It looks like there is no way to print "allocation profiler is not
supported" warning since it could be "regular -prof" gc works while
allocation does not (e.g. jre<1.6u26)


Another quick question:

In GCProfiler we have
if (c > 0) {
    churn.add(name, c);
}

Isn't that a measuring bias?
I think we should measure all the values, otherwise you are just
throwing away zero measurements for no reason.

Vladimir