Tests: Fix RunCMake.try_compile test for C standards with MSVC 19.27

Since commit f7347f28c7 (MSVC: Record support for C11 and c_restrict,
2020-08-09) we know about MSVC C language standards.  Update the
`RunCMake.try_compile` test to be aware of this even when CMake is
itself configured by an older CMake that does not know this.
1 file changed