Retire legacy test infrastructure

* Removed zpios kmod, utility, headers and man page.

* Removed unused scripts zpios-profile/*, zpios-test/*,
  zpool-config/*, smb.sh, zpios-sanity.sh, zpios-survey.sh,
  zpios.sh, and zpool-create.sh.

* Removed zfs-script-config.sh.in.  When building 'make' generates
  a common.sh with in-tree path information from the common.sh.in
  template.  This file and sourced by the test scripts and used
  for in-tree testing, it is not included in the packages.  When
  building packages 'make install' uses the same template to
  create a new common.sh which is appropriate for the packaging.

* Removed unused functions/variables from scripts/common.sh.in.
  Only minimal path information and configuration environment
  variables remain.

* Removed unused scripts from scripts/ directory.

* Remaining shell scripts in the scripts directory updated to
  cleanly pass shellcheck and added to checked scripts.

* Renamed tests/test-runner/cmd/ to tests/test-runner/bin/ to
  match install location name.

* Removed last traces of the --enable-debug-dmu-tx configure
  options which was retired some time ago.

Reviewed-by: Giuseppe Di Natale <dinatale2@llnl.gov>
Signed-off-by: Brian Behlendorf <behlendorf1@llnl.gov>
Closes #6509

configure.ac

@@ -104,7 +104,6 @@ AC_CONFIG_FILES([
 	cmd/zpool/Makefile
 	cmd/zstreamdump/Makefile
 	cmd/ztest/Makefile
-	cmd/zpios/Makefile
 	cmd/mount_zfs/Makefile
 	cmd/fsck_zfs/Makefile
 	cmd/zvol_id/Makefile
@@ -127,7 +126,6 @@ AC_CONFIG_FILES([
 	module/unicode/Makefile
 	module/zcommon/Makefile
 	module/zfs/Makefile
-	module/zpios/Makefile
 	module/icp/Makefile
 	include/Makefile
 	include/linux/Makefile
@@ -138,13 +136,9 @@ AC_CONFIG_FILES([
 	include/sys/crypto/Makefile
 	include/sys/sysevent/Makefile
 	scripts/Makefile
-	scripts/zpios-profile/Makefile
-	scripts/zpios-test/Makefile
-	scripts/zpool-config/Makefile
-	scripts/common.sh
 	tests/Makefile
 	tests/test-runner/Makefile
-	tests/test-runner/cmd/Makefile
+	tests/test-runner/bin/Makefile
 	tests/test-runner/include/Makefile
 	tests/test-runner/man/Makefile
 	tests/runfiles/Makefile
@@ -310,7 +304,6 @@ AC_CONFIG_FILES([
 	rpm/generic/zfs.spec
 	rpm/generic/zfs-kmod.spec
 	rpm/generic/zfs-dkms.spec
-	zfs-script-config.sh
 	zfs.release
 ])