[PATCH v2 0/6] --valgrind improvements

Here's the promised reroll. It integrates everyone's suggestions (I hope I didn't miss any), most notably the two by Peff:

* --valgrind-parallel only does the valgrind wrapper setup in the
  children, avoiding lock contention and confusion because it tries to
  wrap the wrappers.

* more careful --verbose-only toggling (with some extra care about the
  blank lines in between)

Thomas Rast (6):
  test-lib: enable MALLOC_* for the actual tests
  test-lib: refactor $GIT_SKIP_TESTS matching
  test-lib: verbose mode for only tests matching a pattern
  test-lib: valgrind for only tests matching a pattern
  test-lib: allow prefixing a custom string before "ok N" etc.
  test-lib: support running tests under valgrind in parallel

 t/README                |  10 ++
 t/test-lib-functions.sh |   2 +
 t/test-lib.sh           | 248 ++++++++++++++++++++++++++++++++++++++----------
 t/valgrind/valgrind.sh  |   3 +
 4 files changed, 213 insertions(+), 50 deletions(-)