Restore support for testing which procedure in certain cases

The which procedure previously could not locate a file by its absolute
file name if that name contains spaces.  This has been fixed and the
test is now run in this situation.

ChangeLog

diff --git a/ChangeLog b/ChangeLog
index 373647e..14c8bec 100644
--- a/ChangeLog
+++ b/ChangeLog
@@ -10,6 +10,10 @@
 	* testsuite/runtest.libs/mockvfs.tcl (mockvfs_op_file): Add
 	isdirectory and isfile operations to the implemented subset.
 
+	* testsuite/runtest.libs/utils.test: Support for testing the which
+	procedure with an absolute file name when the full absolute name
+	of the object directory contains whitespace is restored.
+
 2026-09-05  Jacob Bachmeyer  <jcb@gnu.org>
 
 	PR44602 / PR47385

testsuite/runtest.libs/utils.test

diff --git a/testsuite/runtest.libs/utils.test b/testsuite/runtest.libs/utils.test
index 8f1d3d2..644a55c 100644
--- a/testsuite/runtest.libs/utils.test
+++ b/testsuite/runtest.libs/utils.test
@@ -135,12 +135,7 @@
 
 # Test 'which' using an absolute path.
 #
-if {[regexp {[[:space:]]} $objdir]} {
-    # unfortunately, the which procedure explicitly truncates its argument
-    # at the first whitespace and ChangeLog-1992 appears to indicate that
-    # it has done so since 11 Jul 1993.
-    unsupported "which, absolute path to config.status"
-} elseif {[which [file join $objdir .. config.status]] != 0} {
+if {[which [file join $objdir .. config.status]] != 0} {
   pass "which, absolute path to config.status"
 } else {
   fail "which, absolute path to config.status"