Fix ppc32 synthetic symbols when __tls_get_addr_opt stub is generated

Fix ppc32 synthetic symbols when __tls_get_addr_opt stub is generated

Also update the 32-bit tls testcases to be secure plt.

bfd/
	* elf32-ppc.c (ppc_elf_get_synthetic_symtab): Examine stubs in
	reverse order.  Account for larger size of __tls_get_addr_opt stub.
ld/testsuite/
	* ld-powerpc/tls32.s: Add GOT pointer setup.
	* ld-powerpc/tls32.d: Update.
	* ld-powerpc/tls32.g: Update.
	* ld-powerpc/tls32.t: Update.
	* ld-powerpc/tlsexe.d: Update.
	* ld-powerpc/tlsexe32.d: Update.
	* ld-powerpc/tlsexe32.g: Update.
	* ld-powerpc/tlsexe32.r: Update.
	* ld-powerpc/tlsexetoc.d: Update.
	* ld-powerpc/tlsso32.d: Update.
	* ld-powerpc/tlsso32.g: Update.
	* ld-powerpc/tlsso32.r: Update.