Add type to expression dump of symbol

I recently had cause to dump some expressions from gdb.  I got output
like this:

 Operation: BINOP_GTR
  Operation: OP_VAR_VALUE
   Block symbol:
    Symbol: small_value
    Block: 0x39b4c20
  Operation: OP_LONG
   Operation: OP_LONG
    Type: int
    Constant: 0x0000000000000014

This is ok, but it would have been handy to see the type of the
symbol.  This patch adds this information.

Reviewed-By: Bruno Larsen <blarsen@redhat.com>