Reapply [lldb][DWARF] Delay struct/class/union definition DIE searching when...

 Reapply [lldb][DWARF] Delay struct/class/union definition DIE searching when parsing declaration DIEs. (#92328)

This reapplies
https://github.com/llvm/llvm-project/commit/9a7262c2601874e5aa64c5db19746770212d4b44
(#90663) and added https://github.com/llvm/llvm-project/pull/91808 as a
fix.

It was causing tests on macos to fail because
`SymbolFileDWARF::GetForwardDeclCompilerTypeToDIE` returned the map
owned by this symol file. When there were two symbol files, two
different maps were created for caching from compiler type to DIE even
if they are for the same module. The solution is to do the same as
`SymbolFileDWARF::GetUniqueDWARFASTTypeMap`: inquery
SymbolFileDWARFDebugMap first to get the shared underlying SymbolFile so
the map is shared among multiple SymbolFileDWARF.