Fix msc-version.c test to handle _MSC_VER=1910

Previously, VC++ has always set _MSC_VER to a four-digit value with the two least significant digits set to zero. Visual Studio 2017, however, sets _MSC_VER=1910, and we expect to update the least significant digit as we release major updates for VS 2017. This patch fixes the msc-version.c test to handle non-zero values in the two least significant digits of _MSC_VER.

llvm-svn: 296843