[ruby/prism] Test cp51932

ruby/prism@29ba8cd1f2

Author: wildmaples

test/prism/encoding_test.rb

@@ -37,6 +37,7 @@ class EncodingTest < TestCase
       windows-1252
       CP1251
       CP1252
+      CP51932
     ].each do |encoding|
       define_method "test_encoding_#{encoding}" do
         result = Prism.parse("# encoding: #{encoding}\n'string'")