SI-7814 Updates the instrumented version of ScalaRuntime.

Some tests for specialization use a modified version of
the standard library that count boxing, array lookups etc.

These sources are updated manually with the script:

    % test/instrumented/mkinstrumented.sh build

Looks that that wasn't done for a while, though.

This commit brings it up to date, and adjusts a few braces in
ScalaRuntime.scala so the patch srt.scala (used by that script)
is shorter.

We should really avoid checking in the products of that script and
run it as part of the build, or, better, use the bytecode
instrumentation framework instead of a modified standard library.
But I have to leave that for another day.