patch 7.4.2086

Problem:    Using the system default encoding makes tests unpredictable.
Solution:   Always use utf-8 or latin1 in the new style tests.  Remove setting
            encoding and scriptencoding where it is not needed.

src/testdir/test_json.vim

@@ -1,12 +1,9 @@
 " Test for JSON functions.
 
-" JSON requires using utf-8.  Conversion breaks the asserts, therefore set
-" 'encoding' to utf-8.
+" JSON requires using utf-8, because conversion breaks the asserts.
 if !has('multi_byte')
   finish
 endif
-set encoding=utf-8
-scriptencoding utf-8
 
 let s:json1 = '"str\"in\\g"'
 let s:var1 = "str\"in\\g"