RFC: testsuite utils

[Benjamin Kosnik]

There's been a large growth in the testsuite directory of files that
are used as part of the test process.... the testsuite_* files.

%ls testsuite_*
testsuite_abi.cc        testsuite_character.h     testsuite_performance.h
testsuite_abi_check.cc  testsuite_common_types.h  testsuite_shared.cc
testsuite_abi.h         testsuite_hooks.cc        testsuite_tr1.h
testsuite_allocator.cc  testsuite_hooks.h         testsuite_visualization.h
testsuite_allocator.h   testsuite_io.h
testsuite_character.cc  testsuite_iterators.h

Is there a better way to organize this, so that future growth in this
are doesn't swamp this directory? I think so, but am uncertain of the
exact form.

One way:

libstdc++-v3/testsuite/util

Another way might be to just do this as a top-level lib. Say, libtestc++. 

Thoughts? Suggestions?

I would also like to see the return of an actual library binary,
instead of a growing collection of .o's. Any objections? Doesn't seem
too controversial.

-benjamin