Fuzzer: Fix escaping of wasm-ctor-eval names (#7223)

Apparently we have some exports that need escaping in their names, and
we should not escape them twice.

Author: kripken

scripts/fuzz_opt.py

@@ -1343,6 +1343,11 @@ def handle(self, wasm):
         if not ctors:
             return
 
+        # Fix escaping of the names, as we will be passing them as commandline
+        # parameters below (e.g. we want --ctors=foo\28bar and not
+        # --ctors=foo\\28bar; that extra escaping \ would cause an error).
+        ctors = ctors.replace('\\\\', '\\')
+
         # eval the wasm.
         # we can use --ignore-external-input because the fuzzer passes in 0 to
         # all params, which is the same as ctor-eval assumes in this mode.