PR c++/66139 - EH cleanups for partially constructed aggregates.

PR c++/66139 - EH cleanups for partially constructed aggregates.

There were several overlapping PRs about failure to clean up fully
constructed subobjects when an exception is thrown during aggregate
initialization of a temporary.  I fixed this for non-temporaries in the
context of 57510, but that fix didn't handle temporaries.  So this patch
does split_nonconstant_init at gimplification time, which is much smaller
than alternatives I tried.

	PR c++/57510
	* cp-gimplify.c (cp_gimplify_init_expr): Use split_nonconstant_init.
	* typeck2.c (split_nonconstant_init): Handle non-variable dest.
	(split_nonconstant_init_1): Clear TREE_SIDE_EFFECTS.
	* tree.c (is_local_temp): New.

From-SVN: r279576