Cherry-pick & resolve merge conflict#1956

Merged

adrian-prantl merged 3 commits intoswiftlang:swift/mainfrom

adrian-prantl:constant_loc-main

Oct 14, 2020

Commits on Oct 13, 2020

[lldb/DWARF] Fix handling of variables with both location and const_value attributes

labath
authored and
adrian-prantl
committed
Remove legacy Swift language constant support
adrian-prantl
committed

Commits on Oct 14, 2020

Move initialization of Variable::m_loc_is_const_data into constructor (NFC)
adrian-prantl
committed