Let Kits automatically use Visual Sudio 2019 compiler with Qt MSVC 2017 packages

Qt Creator should use automatically configure kits using Qt packages compiled for MSVC 2017 to use the Visual Studio 2019 compiler, if it is the only available one.

The output of Visual Studio 2015, 2017 and Visual Studio 2019 compilers are compatible: https://docs.microsoft.com/en-us/cpp/porting/binary-compat-2015-2017?view=vs-2019 . However, currently Qt Creator does assign a different ABI to them. One result is that, if you installed Qt built for Visual Studio 2017 on a PC with only Visual Studio 2019, the Kits won't have a default compiler configured.

Instead, Qt Creator should treat the compilers as compatible (possible name: windows-msvc14.X ).