testsuite,X86: Fix missing USER_LABEL_PREFIX cases.

Yet another set of testcases that do not account for targets that
use __USER_LABEL_PREFIX__.

Signed-off-by: Iain Sandoe <iain@sandoe.co.uk>

gcc/testsuite/ChangeLog:

	* gcc.target/i386/memcpy-strategy-10.c: Account for
	__USER_LABEL_PREFIX__.
	* gcc.target/i386/memcpy-strategy-5.c: Likewise.
	* gcc.target/i386/memset-strategy-5.c: Likewise.
	* gcc.target/i386/memset-strategy-7.c: Likewise.