create new base images for 5.0uX train

The Windows patcher file for 5.0u9 is now 1954KB compressed. It also
takes about 42 seconds of install time to patch 5.0->5.0u9. I believe
this is because we've become more aggressive in Tiger update releases
than we have been in past releases. I also think this is a result of
not having a 1.5.1 or 1.5.2 train like we've done in the past.

So I was wondering what people would think of internally starting a
1.5.1 release in the installer. We'd create a new baseline of 5.0u9,
and all future 5.0uX releases would be a patch of 5.0u9->5.0u?. Only
the installer itself would have knowledge that it is a 1.5.1 release, so
we won't confuse users or anything. All text and plugin/web start
clsid's will still be 150, not 151

I've looked into doing this, and this would initially take the minimum
download size of 5.0u9 from 9118KB -> 7417KB. It would also take off
the 42 seconds of the patching part of the installation process. Future
5.0uX releases would obviously add size and time, but they would likely
be minimal.

There is a downside to this approach though. Currently, any users who
have a 5.0uX release and want to install any new version of 5.0uX will
only have to download the 1954KB patcher file (as long as they use the
online installer). If we create a new 5.0u9 baseline, these users will
have to pay a one-time big price by downloading the full 7417KB JRE for
updating to any 5.0u9+ release. We'll probably start java-updating
people to 6uX in the near future, so I don't think this will matter all
that much. But 5.0uX will be around for many more years, and i think we
should do something to minimize the size.

-Bill
PS. 5.0u9 baseline doesn't necessarily have to be 5.0u9. It could be
u10 or u11.