Issue #855

This reduces the amount of voodoo in compiletest considerably.

This will make it a bit clearer what's going on

Emacs gets confused by <input>:0:0:0:0:

This reverts commit d5173b1f.

This reverts commit 4e136d1f.

This fixes up the current leaks.

We continue to leak string buffers in trans so this creates a way to get c
string buffers from strings while guaranteeing that they are not freed before
use.

Hopefully this can be made efficient in the istr regime.

It's been around forever. I don't know what it is, but I need the compiler to
be valgrind clean for the istr transition so I'm suppressing it.

There's nothing to be done for stage0 at this point.

This reverts commit b0db1395.

(Should work now that we have a new snapshot)