[WPD][ELF] Allow whole program devirtualization for version script localized symbols

A `local:` version node in a version script can change the effective symbol binding
to STB_LOCAL. The linker needs to communicate the fact to enable WPD
(otherwise LTO does not know that the `!vcall_visibility` metadata has
effectively changed from VCallVisibilityPublic to VCallVisibilityLinkageUnit).

Reviewed By: tejohnson

Differential Revision: https://reviews.llvm.org/D98220