PR28827 testcase

This testcase triggers a stub sizing error with the patches applied
for PR28743 (commit 2f83249c and c804c6f9).

	PR 28827
	* testsuite/ld-powerpc/pr28827-1.s,
	* testsuite/ld-powerpc/pr28827-1.d: New test.
	* testsuite/ld-powerpc/powerpc.exp: Run it.

(cherry picked from commit 9810db10)
(cherry picked from commit 0acf434a)