htl: Enable more tests

* htl/Makefile: Remove rules adding libpthread.so and libpthread.a to link
lines.
* nptl/Makefile: Move rules adding libpthread.so and libpthread.a to
link lines to...
* sysdeps/pthread/Makefile: ... here.

* nptl/eintr.c, tst-align.c tst-align3.c tst-atfork1.c tst-backtrace1.c
tst-bad-schedattr.c tst-cancel-self-canceltype.c tst-cancel-self-cleanup.c
tst-cancel-self-testcancel.c tst-cancel1.c tst-cancel10.c tst-cancel12.c
tst-cancel14.c tst-cancel15.c tst-cancel18.c tst-cancel19.c tst-cancel2.c
tst-cancel22.c tst-cancel23.c tst-cancel26.c tst-cancel27.c tst-cancel28.c
tst-cancel3.c tst-cancel8.c tst-cancelx1.c tst-cancelx10.c tst-cancelx12.c
tst-cancelx14.c tst-cancelx15.c tst-cancelx18.c tst-cancelx2.c tst-cancelx3.c
tst-cancelx8.c tst-cleanup0.c tst-cleanup0.expect tst-cleanup1.c tst-cleanup2.c
tst-cleanup3.c tst-cleanupx0.c tst-cleanupx0.expect tst-cleanupx1.c
tst-cleanupx2.c tst-cleanupx3.c tst-clock1.c tst-create-detached.c tst-detach1.c
tst-eintr2.c tst-eintr3.c tst-eintr4.c tst-eintr5.c tst-exec1.c tst-exec2.c
tst-exec3.c tst-exit1.c tst-exit2.c tst-exit3.c tst-flock1.c tst-fork1.c
tst-fork2.c tst-fork3.c tst-fork4.c tst-getpid3.c tst-kill1.c tst-kill2.c
tst-kill3.c tst-kill4.c tst-kill5.c tst-kill6.c tst-locale1.c tst-locale2.c
tst-memstream.c tst-popen1.c tst-raise1.c tst-sem5.c tst-setuid3.c tst-signal4.c
tst-signal5.c tst-signal6.c tst-signal8.c tst-stack1.c tst-stdio1.c tst-stdio2.c
tst-sysconf.c tst-tls1.c tst-tls2.c tst-tsd1.c tst-tsd2.c tst-tsd5.c tst-tsd6.c
tst-umask1.c tst-unload.c tst-unwind-thread.c tst-vfork1.c tst-vfork1x.c
tst-vfork2.c tst-vfork2x.c: Move tests to...
* sysdeps/pthread: ... here.
Rename
tst-popen1.c -> tst-pt-popen1.c
tst-align.c -> tst-pt-align.c
tst-align3.c -> tst-pt-align3.c
tst-sysconf.c -> tst-pt-sysconf.c
tst-tls1.c -> tst-pt-tls1.c
tst-tls2.c -> tst-pt-tls2.c
tst-vfork1.c -> tst-pt-vfork1.c
tst-vfork2.c -> tst-pt-vfork2.c
to avoid conflicting with libio/tst-popen1.c, elf/tst-align.c,
posix/tst-sysconf.c, elf/tst-tls1.c, elf/tst-tls2.c, posix/tst-vfork1.c,
posix/tst-vfork2.c.

* nptl/Makefile: Move corresponding tests references and special rules to...
* sysdeps/pthread/Makefile: ... here.

* sysdeps/pthread/tst-stack1.c (do_test): Do not clamp stack size to
PTHREAD_STACK_MIN if not defined.

Tested on linux-x86_64 and hurd-i386