tcl8: upgrade 8.6.15 -> 8.6.16

Adjust run-ptest to use the absolute ptest library location
(tcl 9.x already does this) to avoid clock.test failures.

(From OE-Core rev: 6161afaa3d4f6600a3598bf559576fb571968cbb)

Signed-off-by: Alexander Kanavin <alex@linutronix.de>
Signed-off-by: Richard Purdie <richard.purdie@linuxfoundation.org>

meta/recipes-devtools/tcltk8/tcl8/interp.patch

@@ -1,4 +1,4 @@
-From 426aa2ff62dda77fd011e8f630b9d4ea17984817 Mon Sep 17 00:00:00 2001
+From 09049beed723243d092ffaa37939dfe0f2ed6828 Mon Sep 17 00:00:00 2001
 From: Ross Burton <ross.burton@arm.com>
 Date: Mon, 12 Jul 2021 14:50:13 +0100
 Subject: [PATCH] tcl: fix race in interp.test
@@ -13,10 +13,10 @@ Signed-off-by: Ross Burton <ross.burton@arm.com>
  1 file changed, 4 insertions(+), 3 deletions(-)
 
 diff --git a/tests/interp.test b/tests/interp.test
-index d742484..fc90990 100644
+index 24ffb1b..c6460ad 100644
 --- a/tests/interp.test
 +++ b/tests/interp.test
-@@ -3595,17 +3595,18 @@ test interp-36.7 {ChildBgerror sets error handler of child [1999035]} -setup {
+@@ -3614,17 +3614,18 @@ test interp-36.7 {ChildBgerror sets error handler of child [1999035]} -setup {
          variable result
          set result [lindex $args 0]
      }