Fix tests that break unnecessarily for avr.

Fix tests that break unnecessarily for avr.

Require int32plus for tests that assume so, and conditionally skip pr44024.c,
 as it only works if the target allows deletion of null pointer checks.

gcc/testsuite/ChangeLog

	* gcc.dg/init-excess-2.c: Require int32plus.
	* gcc.dg/pr44024.c: Skip if target keeps null pointer checks.
	* gcc.dg/pr59963-2.c: Require int32plus.
	* gcc.dg/pr71084.c: Cast pointer to intprt_t.
	* gcc.dg/unroll-7.c: Require int32plus.

From-SVN: r239065