Ruby

merge revision(s) c7ce2f537f96ab2cf2f5fc2982d6147866ff5340: [Backport #20304] (#10311)

Fix memory leak in setting encodings

 There is a memory leak in Encoding.default_external= and Encoding.default_internal= because the duplicated name is not freed when overwriting. 10.times do 1_000_000.times do Encoding.default_internal = nil end puts `ps -o rss= -p #{$$}` end Before: 25664 41504 57360 73232 89168 105056 120944 136816 152720 168576 After: 9648 9648 9648 9680 9680 9680 9680 9680 9680 9680