[IR] Rename comdat noduplicates to comdat nodeduplicate

In the textual format, `noduplicates` means no COMDAT/section group
deduplication is performed. Therefore, if both sets of sections are retained, and
they happen to define strong external symbols with the same names,
there will be a duplicate definition linker error.

In PE/COFF, the selection kind lowers to `IMAGE_COMDAT_SELECT_NODUPLICATES`.
The name describes the corollary instead of the immediate semantics.  The name
can cause confusion to other binary formats (ELF, wasm) which have implemented/
want to implement the "no deduplication" selection kind. Rename it to be clearer.

Reviewed By: rnk

Differential Revision: https://reviews.llvm.org/D106319

llvm/lib/Bitcode/Reader/BitcodeReader.cpp

@@ -1128,7 +1128,7 @@ static Comdat::SelectionKind getDecodedComdatSelectionKind(unsigned Val) {
   case bitc::COMDAT_SELECTION_KIND_LARGEST:
     return Comdat::Largest;
   case bitc::COMDAT_SELECTION_KIND_NO_DUPLICATES:
-    return Comdat::NoDuplicates;
+    return Comdat::NoDeduplicate;
   case bitc::COMDAT_SELECTION_KIND_SAME_SIZE:
     return Comdat::SameSize;
   }