c++: Only destruct elts of array for new expression if exception is thrown during...

c++: Only destruct elts of array for new expression if exception is thrown during the initialization [PR117827]

The following testcase r12-6328, because the elements of the array
are destructed twice, once when the callee encounters delete[] p;
and then second time when the exception is thrown.
The array elts should be only destructed if exception is thrown from
one of the constructors during the build_vec_init emitted code in case of
new expressions, but when the new expression completes, it is IMO
responsibility of user code to delete[] it when it is no longer needed.

So, the following patch uses the cleanup_flags argument to build_vec_init
to get notified of the flags that need to be changed when the expression
is complete and build_disable_temp_cleanup to do the changes.

2025-01-25  Jakub Jelinek  <jakub@redhat.com>

	PR c++/117827
	* init.cc (build_new_1): Pass address of a make_tree_vector ()
	initialized gc tree vector to build_vec_init and append
	build_disable_temp_cleanup to init_expr from it.

	* g++.dg/init/array66.C: New test.

(cherry picked from commit ce268ca2a923f8f35cc9dd5a7d0468a3980f129f)