Fix bug #7829 - do NOT reject ConstructorInfo in DynamicILInfo.GetTokenFor().

It is only one of probably many reasons that prevents Jurassic JavaScript engine.
Revert "Fix bug #7829 - do NOT reject ConstructorInfo in DynamicILInfo.GetTokenFor()."

This reverts commit b43211d101e5e058b0d57e92a350515ffd71df26.
Remove deprecated -mno-cygwin flag.