ld: Avoid folding new and delete pairs

GCC 15 may fold new and delete pairs, like

  A *bb = new A[10];
  delete [] bb;
  bb = new (std::nothrow) A [10];
  delete [] bb;

as shown in

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=115712



Avoid folding new and delete pairs by adding a function call between new
and delete.

	* testsuite/ld-elf/dl5.cc: Include "dl5.h".
	(A): Removed.
	Call foo between new and delete.
	* testsuite/ld-elf/dl5.h: New file.
	* testsuite/ld-elf/new.cc: Include "dl5.h".
	(foo): New function.

Signed-off-by: H.J. Lu <hjl.tools@gmail.com>
(cherry picked from commit adf584eb)