Merge pull request dotnet/coreclr#6081 from adityamandaleeka/virtual_temp

Clean up unused code related to memory mapping

Commit migrated from https://github.com/dotnet/coreclr/commit/6f26329518b08055c090315eee5db533e42f39ae

diff --cc src/coreclr/src/pal/src/config.h.in
Simple merge

diff --cc src/coreclr/src/pal/src/configure.cmake
Simple merge

diff --cc src/coreclr/src/pal/src/include/pal/virtual.h
Simple merge

diff --cc src/coreclr/src/pal/src/map/virtual.cpp
Simple merge