testsuite: Add default_packed filters

Fix test cases assumptions that target has alignment constraints.

gcc/testsuite/ChangeLog:

	* gcc.dg/attr-copy-4.c: Unpacked may still have alignment of 1
	on targets with default_packed.
	* gcc.dg/c11-align-9.c: Remove AVR target filter and replace
	with default_packed filter.

Signed-off-by: Dimitar Dimitrov <dimitar@dinux.eu>

gcc/testsuite/gcc.dg/attr-copy-4.c

@@ -32,6 +32,7 @@ extern const struct PackedA packed;
 
 struct Unpacked { int i; char c; };
 Assert (__alignof (struct Unpacked) > 1);
+/* { dg-error "size of array .* is negative" "" { target default_packed } .-1 } */
 
 /* Verify that copying the packed attribute to the declaration
    of an object is ignored with a warning.  (There should be

gcc/testsuite/gcc.dg/c11-align-9.c

@@ -2,8 +2,8 @@
    are at least some alignment constraints), case of compound literals.  */
 /* { dg-do compile } */
 /* { dg-options "-std=c11 -pedantic-errors" } */
-/* { dg-skip-if "no alignment constraints" { "avr-*-*" } } */
 
 #include <stddef.h>
 
-max_align_t *p = &(_Alignas (_Alignof (char)) max_align_t) { 1 }; /* { dg-error "reduce alignment" } */
+max_align_t *p = &(_Alignas (_Alignof (char)) max_align_t) { 1 };
+/* { dg-error "reduce alignment" "" { target { ! default_packed } } .-1 } */