Add HttpResponse.BodyHandlers.ofFile(Path) to banned method lists (buggy)

[dweiss]

Eh. Perhaps worth adding to forbidden method list with a comment saying it's likely buggy in whatever JDK one is using:
https://bugs.openjdk.org/browse/JDK-8299015

[uschindler]

Hey, let me see. Of course it will be fixed in 21, so we need some trick there to undo the addition (it reads signatures incrementally).

I added this method to the Java 11 unsafe methods. I will think about a solution for 21.

[uschindler]

See this commit: 020f4cb