Improve System.arraycopy's ArrayIndexOutOfBoundsException messages.

This has been handy for me a few times, and with Froyo's bug reporting
improvements, more third-party developers will be trying to debug remotely
and after the fact, so this might help them too.

Change-Id: I17abe6e91e487c02b782f62245392fbcbe5baf8e
1 file changed