[Gardening] How to ressurect tests and benchmark

Author: palimondo

test/Prototypes/DoubleWidth.swift.gyb

@@ -4,6 +4,10 @@
 
 import StdlibUnittest
 
+// XXX: Auxiliary tests & benchmark for DoubleWidth were removed in PR #23024.
+// When the DoubleWidth makes comeback, revert the commits from there to
+// ressurect what was just a dead code in the meantime…
+
 /// A fixed-width integer that has twice the bit width of its base type.
 ///
 /// You can use the `DoubleWidth` type to continue calculations with the result