Streamline Windows vtable slice handling

src/smgdc/vtable.py

@@ -35,14 +35,10 @@ def reorder_vfns_windows_estimate(symbols: list[Symbol], start_pos: int) -> list
             # HACK: preserves positions of references to __cxa_pure_virtual
             name_buckets[(dmsym, n)].append(symbol)
 
-    output_symbols: list[Symbol] = []
-    for fname, syms in name_buckets.items():
-        # on windows, overloads are made consecutive and in reverse of declared order
-        # iteration order is guaranteed as of py3.7+ to be the insertion order,
-        # so this should output symbols otherwise in their original order
-        output_symbols.extend(reversed(syms))
-
-    return output_symbols
+    # on windows, overloads are made consecutive and in reverse of declared order
+    # iteration order is guaranteed as of py3.7+ to be the insertion order,
+    # so this should output symbols otherwise in their original order
+    return list(itertools.chain.from_iterable(reversed(syms) for syms in name_buckets.values()))
 
 
 def get_windows_vtables_from(bin: "LinuxBinary", vt: Symbol) -> VTable: