We don't want to handle Linux syscalls when in the virtual environment,
just the user environment, so adjust the Linux traps logic to check for
that specifically (instead of just skipping the operating environment).
Also tweak some testcases to explicitly specify the environment they run
under rather than relying on the default matching their needs. This gets
the tests passing for all m32r targets.
Now that all port tests live under testsuite/sim/*/, and none live
in testsuite/ directly, flatten the structure by moving all of the
dirs under testsuite/sim/ to testsuite/ directly.
We need to stop passing --tool to dejagnu so that it searches all
dirs and not just ones that start with "sim". Since we have no
other dirs in this tree, and no plans to add any, should be fine.
