* posix/Makefile (tests): Add tst-execvp1, tst-execvp2, tst-execlp1,

* posix/Makefile (tests): Add tst-execvp1, tst-execvp2, tst-execlp1,

	tst-execlp2, tst-execv1, tst-execv2, tst-execl1, tst-execl2,
	tst-execve1, tst-execve2, tst-execle1, and tst-execle2.
	* posix/tst-execl1.c: New file.
	* posix/tst-execl2.c: New file.
	* posix/tst-execle1.c: New file.
	* posix/tst-execle2.c: New file.
	* posix/tst-execlp1.c: New file.
	* posix/tst-execlp2.c: New file.
	* posix/tst-execv1.c: New file.
	* posix/tst-execv2.c: New file.
	* posix/tst-execve1.c: New file.
	* posix/tst-execve2.c: New file.
	* posix/tst-execvp1.c: New file.
	* posix/tst-execvp2.c: New file.