Add checks in IO to match new specs

Author: eregon

src/main/ruby/truffleruby/core/io.rb

@@ -1065,6 +1065,7 @@ def binmode
   end
 
   def binmode?
+    ensure_open
     !Primitive.nil?(@binmode)
   end
 
@@ -1454,6 +1455,7 @@ def eof?
   end
 
   def external_encoding
+    ensure_open
     if @mode & FMODE_WRITABLE == 0
       @external || Encoding.default_external
     else
@@ -1487,6 +1489,7 @@ def fcntl(command, arg=0)
   end
 
   def internal_encoding
+    ensure_open
     @internal
   end
 
@@ -1611,7 +1614,7 @@ def gets(sep_or_limit=$/, limit=nil)
   #  f.gets     #=> "This is line two\n"
   #  f.lineno   #=> 2
   def lineno
-    ensure_open
+    ensure_open_and_readable
     @lineno
   end
 
@@ -1628,7 +1631,7 @@ def lineno
   #  f.gets                     #=> "This is line two\n"
   #  $. # lineno of last read   #=> 1001
   def lineno=(line_number)
-    ensure_open
+    ensure_open_and_readable
     @lineno = Integer(line_number)
   end