The experiment deployment of TclDuplicatePureObj() has been reverted from

the trunk.  This branch attempts to prepare a reversion for the
core-8-branch also, via a cherrypick and resolution of conflicts.

Starting an experiment in one new release to reject it
in the next is at best odd.  Also, valgrind test runs of core-8-branch
show memory leaks with TclDuplicatePureObj() on the stack trace.  This
checkin shows a clean valgrind run.

There are three test failures on this checkin, which I hope someone versed
in the ArithSeries work can resolve.  They are the tests:

lseq-3.14
lseq-4.19
lseq-bug-54329e39c7

merge bug-bc7ddc7944 (revert use of TclDuplicatePureObj)

1 files changed, 1 insertions, 5 deletions

diff --git a/generic/tclUtil.c b/generic/tclUtil.c
index cfc56b0..f9f6ae0 100644
--- a/generic/tclUtil.c
+++ b/generic/tclUtil.c
@@ -2051,11 +2051,7 @@ Tcl_ConcatObj(
 		    goto slow;
 		}
 	    } else {
-		resPtr = TclDuplicatePureObj(
-		    NULL, objPtr, &tclListType);
-		if (!resPtr) {
-		    return NULL;
-		}
+		resPtr = TclListObjCopy(NULL, objPtr);
 	    }
 	}
 	if (!resPtr) {