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

include/Makefile.am

@@ -6,11 +6,7 @@ COMMON_H = \
 	$(top_srcdir)/include/zfs_deleg.h \
 	$(top_srcdir)/include/zfs_fletcher.h \
 	$(top_srcdir)/include/zfs_namecheck.h \
-	$(top_srcdir)/include/zfs_prop.h \
-	$(top_srcdir)/include/zpios-ctl.h
-
-KERNEL_H = \
-	$(top_srcdir)/include/zpios-internal.h
+	$(top_srcdir)/include/zfs_prop.h
 
 USER_H = \
 	$(top_srcdir)/include/libnvpair.h \
@@ -22,7 +18,7 @@ USER_H = \
 	$(top_srcdir)/include/libzfs_impl.h \
 	$(top_srcdir)/include/thread_pool.h
 
-EXTRA_DIST = $(COMMON_H) $(KERNEL_H) $(USER_H)
+EXTRA_DIST = $(COMMON_H) $(USER_H)
 
 if CONFIG_USER
 libzfsdir = $(includedir)/libzfs
@@ -31,5 +27,5 @@ endif
 
 if CONFIG_KERNEL
 kerneldir = @prefix@/src/zfs-$(VERSION)/include
-kernel_HEADERS = $(COMMON_H) $(KERNEL_H)
+kernel_HEADERS = $(COMMON_H)
 endif