Remove redundant calls of String#chr

git-svn-id: svn+ssh://ci.ruby-lang.org/ruby/trunk@60227 b2dd03c8-39d4-4d8f-98ff-823fe69b080e

ext/pty/lib/expect.rb

@@ -43,13 +43,13 @@ class IO
     @unusedBuf ||= ''
     while true
       if not @unusedBuf.empty?
-        c = @unusedBuf.slice!(0).chr
+        c = @unusedBuf.slice!(0)
       elsif !IO.select([self],nil,nil,timeout) or eof? then
         result = nil
         @unusedBuf = buf
         break
       else
-        c = getc.chr
+        c = getc
       end
       buf << c
       if $expect_verbose