S390: Test that lazy binding does not clobber R0

The following combinations need to be tested:
* 32- (g5, esa and zarch) and 64-bit
  * linux32 glibc/configure CC='gcc -m31 -march=g5'
  * linux32 glibc/configure CC='gcc -m31'
  * linux32 glibc/configure CC='gcc -m31 -mzarch'
* With and without VX:
  * glibc/configure libc_cv_asm_s390_vx=no
* With and without profiling (using LD_PROFILE)
* With and without pltexit (using LD_AUDIT)

ChangeLog:

	* sysdeps/s390/Makefile: Register the new tests.
	* sysdeps/s390/tst-dl-runtime-mod.S: New file.
	* sysdeps/s390/tst-dl-runtime-profile-audit.c: New file.
	* sysdeps/s390/tst-dl-runtime-profile-noaudit.c: New file.
	* sysdeps/s390/tst-dl-runtime-resolve-audit.c: New file.
	* sysdeps/s390/tst-dl-runtime-resolve-noaudit.c: New file.
	* sysdeps/s390/tst-dl-runtime.c: New file.