win,build,tools: support VS prerelease

Checklist

• make -j4 test (UNIX), or vcbuild test (Windows) passes
• commit message follows commit guidelines

I don't know if we supporting prerelease (Preview) versions, but I see there is a flow for that, so I just adjust it.

Without my change, I have both Visual Studio 19 Preview and Visual Studio 17 Enterprise, but I getting the next error:

❯ .\vcbuild.bat
Looking for Python
Python found in C:\Users\BaruchR\AppData\Local\Programs\Python\Python37\\python.exe
Looking for NASM
Looking for Visual Studio 2019
Failed to find a suitable Visual Studio installation.
Try to run in a "Developer Command Prompt" or consult
https://github.com/nodejs/node/blob/master/BUILDING.md#windows