ia64 assembler warning breaks ld tests

ia64 assembler warning breaks ld tests

The "Warning: Explicit stops are ignored in auto mode" results in
failures of a number of run_ld_link_tests because the compiler is run
using -S and then the resulting .s file assembled without suppplying
-x to gas.  Fix that problem by adding -x to ASFLAGS for ia64, and
tweak the binutils link-order test since the source is used in a ld
test too.

ld/
	* testsuite/config/default.exp: Set ASFLAGS to "-x" for ia64.
	Remove unnecessary "global".
binutils/
	* testsuite/binutils-all/link-order.s: Provide explicit stop.
	* testsuite/binutils-all/objcopy.exp: Pass "-x" when building
	link-order test for ia64.