Since start.o may be compiled as PIC, we should check PIC instead of
SHARED.
[BZ #22638]
* sysdeps/sparc/sparc32/start.S (_start): Check PIC instead of
SHARED.
* sysdeps/sparc/sparc64/start.S (_start): Likewise.
(cherry picked from commit 371b220f6208968d5f4bffc9f66bf885930a42a5)