dynamic array's upper bound evaluated as address for AVR target

["Sivanupandi, Pitchumani" <Pitchumani.Sivanupandi@atmel.com>]

Tests from gdb.base/vla-datatypes.exp are failed for AVR target.
Test vla-datatypes.c validates size and values of dynamic arrays.

When evaluating the array expression (e.g. print int_vla), debug info for
upper bound of array read as location expression. By default, the location
expressions are treated as DWARF_VALUE_MEMORY (dwarf2expr.c:execute_stack_op).
and converted to target address (dwarf2loc.c:dwarf2_locexpr_baton_eval).

This will lead to incorrect upper bound value for targets like AVR where 
integer_to_address hook defined. For array 'int_vla', upper bound (e.g. 4)
is wrongly converted to avr target sram address (0x80004). And gdb tries to
read 0x100008 (0x80004 * 2) bytes of values from array's start address.
This is incorrect and caused timeout for avr target.

Why is that location expression treated as DWARF_VALUE_MEMORY by default?
Can gdb detect if location expression for literal value (e.g. array bounds)
or not?

Regards,
Pitchumani