Re: PR28827, assertion building LLVM 9 on powerpc64le-linux-gnu

In trying to find a testcase for PR28827, I managed to hit a linker
error in bfd_set_section_contents with a .branch_lt input section
being too large for the output .branch_lt.

bfd/
	PR 28827
	* elf64-ppc.c (ppc64_elf_size_stubs): Set section size to
	maxsize past STUB_SHRINK_ITER before laying out.  Remove now
	unnecessary conditional setting of maxsize at start of loop.
ld/
	* testsuite/ld-powerpc/pr28827-2.d,
	* testsuite/ld-powerpc/pr28827-2.lnk,
	* testsuite/ld-powerpc/pr28827-2.s: New test.
	* testsuite/ld-powerpc/powerpc.exp: Run it.