[WebAssembly] Fix R_WASM_FUNCTION_OFFSET_I32 relocation warnings

[sbc100]

Summary

We were incorrectly used the symbol table version of the function rather
than the object-local version when checking the existing relocation
value.

This was causing erroneous warnings for comat symbols defined in
multiple object.s

Fixes: #40503

[kripken]

Not an expert on this code but it looks right to me.

lld/wasm/InputFiles.cpp

case R_WASM_MEMORY_ADDR_REL_SLEB: {
     const WasmSymbol &Sym = WasmObj->syms()[Reloc.Index];
     if (Sym.isUndefined())
       return 0;
     const WasmSegment &Segment =
         WasmObj->dataSegments()[Sym.Info.DataRef.Segment];
     return Segment.Data.Offset.Value.Int32 + Sym.Info.DataRef.Offset +
            Reloc.Addend;
   }
-  case R_WASM_FUNCTION_OFFSET_I32:
-    if (auto *Sym = dyn_cast<DefinedFunction>(getFunctionSymbol(Reloc.Index))) {
-      return Sym->Function->getFunctionInputOffset() +
-             Sym->Function->getFunctionCodeOffset() + Reloc.Addend;
-    }
-    return 0;
+  case R_WASM_FUNCTION_OFFSET_I32: {
+    const WasmSymbol &Sym = WasmObj->syms()[Reloc.Index];
+    InputFunction *F =
+        Functions[Sym.Info.ElementIndex - WasmObj->getNumImportedFunctions()];
+    return F->getFunctionInputOffset() + F->getFunctionCodeOffset() +
+           Reloc.Addend;
   case R_WASM_SECTION_OFFSET_I32:
     return Reloc.Addend;
   case R_WASM_TYPE_INDEX_LEB:
     return Reloc.Index;
   case R_WASM_FUNCTION_INDEX_LEB:
   case R_WASM_GLOBAL_INDEX_LEB:
   case R_WASM_EVENT_INDEX_LEB: {
     const WasmSymbol &Sym = WasmObj->syms()[Reloc.Index];