[lld][WebAssembly] Do not merge comdat data segments

When running in relocatable mode any input data segments that are part
of a comdat group should not be merged with other segments of the same
name.  This is because the final linker needs to keep the separate so
they can be included/excluded individually.

Often this is not a problem since normally only one section with a given
name `foo` ends up in the output object file.  However, the problem
occurs when one input contains `foo` which part of a comdat and another
object contains a local symbol `foo` we were attempting to merge them.

This behaviour matches (I believe) that of the ELF linker.  See
`LinkerScript.cpp:addInputSec`.

Fixes: https://github.com/emscripten-core/emscripten/issues/9726

Differential Revision: https://reviews.llvm.org/D101703

lib/Object/WasmObjectFile.cpp

@@ -39,8 +39,8 @@ using namespace object;
 
 void WasmSymbol::print(raw_ostream &Out) const {
   Out << "Name=" << Info.Name
-      << ", Kind=" << toString(wasm::WasmSymbolType(Info.Kind))
-      << ", Flags=" << Info.Flags;
+      << ", Kind=" << toString(wasm::WasmSymbolType(Info.Kind)) << ", Flags=0x"
+      << Twine::utohexstr(Info.Flags);
   if (!isTypeData()) {
     Out << ", ElemIndex=" << Info.ElementIndex;
   } else if (isDefined()) {