Allow strings with printf/eval

PR 13098 explains that if a user attempts to use a string with either
`printf' (or `eval'), gdb returns an error (inferior not running):

(gdb) printf "%s\n", "hello"
evaluation of this expression requires the target program to be active

However, the parser can certainly handle this case:

(gdb) p "hello"
$1 = "hello"

This discrepancy occurs because printf_c_string does not handle
this specific case.  The passed-in value that we are attempting to print
as a string is TYPE_CODE_ARRAY but it's lval type is not_lval.

printf_c_string will only attempt to print a string from the value's
contents when !TYPE_CODE_PTR, lval is lval_internalvar, and the value's
type is considered a string type:

  if (value->type ()->code () != TYPE_CODE_PTR
      && value->lval () == lval_internalvar
      && c_is_string_type_p (value->type ()))
    {
      ...
    }

Otherwise, it attempts to read the value of the string from the target's
memory (which is what actually generates the "evaluation of this ..."
error message).

gdb/printcmd.c

@@ -2447,8 +2447,8 @@ printf_c_string (struct ui_file *stream, const char *format,
 {
   const gdb_byte *str;
 
-  if (value->type ()->code () != TYPE_CODE_PTR
-      && value->lval () == lval_internalvar
+  if (((value->type ()->code () != TYPE_CODE_PTR && value->lval () == lval_internalvar)
+       || value->type ()->code () == TYPE_CODE_ARRAY)
       && c_is_string_type_p (value->type ()))
     {
       size_t len = value->type ()->length ();