[PATCH v4] msvcrt: Use already existent oneexit_table functions for _onexit and _c_exit

[Piotr Caban]

From: Fabian Maurer

Signed-off-by: Fabian Maurer 
Signed-off-by: Piotr Caban

v4:
  - don't use __MSVCRT_ prefix for internal functions
  - simplified atexit functions order test
---
  dlls/msvcrt/exit.c         | 201 
+++++++++++++++++++++------------------------
  dlls/ucrtbase/tests/misc.c |  56 ++++++++++++-
  2 files changed, 149 insertions(+), 108 deletions(-)