[PATCH v2] msvcrt: Update source pointer in wcsrtombs in C locale.

[Piotr Caban]

From: Bernhard Kölbl <besentv(a)gmail.com>

Wine-Bug: https://bugs.winehq.org/show_bug.cgi?id=50698
Signed-off-by: Piotr Caban <piotr(a)codeweavers.com>
---
  dlls/msvcrt/tests/string.c | 16 ++++++++++++++++
  dlls/msvcrt/wcs.c          |  3 +++
  2 files changed, 19 insertions(+)