IRSL: Fix discovery of VS 2019 v141 toolset redistributables
This updates the logic in InstallRequiredSystemLibraries
so that the v141 redistributable path is searched for in multiple VS versions (VS2017 and VS2019).
A second minor commit fixes a typo that would prevent a warning message when the MSVC_TOOLSET_VERSION
is greater than or equal to 143.
Fixes: #19488 (closed)
Topic-rename: InstallRequiredSystemLibraries-redist
Edited by Brad King