compress.gzip / deflate: rename gzip module into deflate module (#14682)

vlib/compress/gzip/gzip_test.v

@@ -1,8 +0,0 @@
-module gzip
-
-fn test_gzip() ? {
-	uncompressed := 'Hello world!'
-	compressed := compress(uncompressed.bytes())?
-	decompressed := decompress(compressed)?
-	assert decompressed == uncompressed.bytes()
-}