[BUG] MSVC_RUNTIME_LIBRARY in tests

[friendlyanon]

Describe the bug

• The MSVC_RUNTIME_LIBRARY property is only available since CMake 3.15, but I forgot to check this in my PR and the minimum required CMake version in the test CML is 3.14.
• The value of this property is not among the supported set of values.

To Reproduce -

Expected behavior

• The minimum requirement shouldn't be a lie.
• The value of the property (if this property is even necessary) should be valid.

Additional context Is this property even necessary?
The VS generator for CMake already uses /MDd for Debug configuration and /MD for everything else.
Is statically linking the CRT for the tests important?

[erikzenker]

I am not an expert for msvc. I just added MSVC_RUNTIME_LIBRARY to satisfy the compiler and get CI. If we just need to set minimum cmake version to 3.15 that would be okay for me.

[friendlyanon]

I just built and ran the tests without the property, I think it can be safely dropped.