CMakeDetermineCompilerId: Support versioned LLVM for Visual Studio.

Supports versioned LLVM toolsets like LLVM_v142, LLVM_v141,
LLVM_v141_xp, etc. for Visual Studio (2010 and later).

The name for versioned LLVM toolsets has "LLVM_" prefix
plus MSVC toolset name (i.e. v142, v141, v141_xp, etc.).

Fixes: #19203
11 jobs for DetermineCompilerId-versioned-llvm-for-vs
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