[clang/DIVar] Emit the flag for params that have unmodified value
Emit the debug info flag that indicates that a parameter has unchanged
value throughout a function.
([5/13] Introduce the debug entry values.)
Co-authored-by: Ananth Sowda <email@example.com>
Co-authored-by: Nikola Prica <firstname.lastname@example.org>
Co-authored-by: Ivan Baev <email@example.com>
Differential Revision: https://reviews.llvm.org/D58035