test: show both CMake and Autotools usage for ctime_tests #1804

1. 
   8144225309 commented at 3:39 pm on January 22, 2026: none

   When building with CMake and running ctime_tests outside valgrind, users see:

   0Usage: libtool --mode=execute valgrind ./ctime_tests
   

   CMake users don’t have libtool. Show both commands.

   Before

   0$ ./build/bin/ctime_tests
   1This test can only usefully be run inside valgrind because it was not compiled under msan.
   2Usage: libtool --mode=execute valgrind ./ctime_tests
   

   After

   0$ ./build/bin/ctime_tests
   1This test can only usefully be run inside valgrind because it was not compiled under msan.
   2Usage: valgrind ./ctime_tests (or with Autotools: libtool --mode=execute valgrind ./ctime_tests)
   

   Fixes #1697

2. test: show both Autotools and CMake usage for ctime_tests

   The existing message only shows the libtool command, which is
   specific to Autotools builds.
   
   Fixes #1697

   1bc74a22f8
3. real-or-random added the label tweak/refactor on Jan 22, 2026
4. real-or-random added the label meta/development on Jan 22, 2026
5. real-or-random removed the label meta/development on Jan 22, 2026
6. real-or-random added the label user-documentation on Jan 22, 2026
7. real-or-random approved
8. 
   real-or-random commented at 4:20 pm on January 22, 2026: contributor

   utACK 1bc74a22f87dd7c3da706095a06765db1bbfc7c1

Contributors
8144225309 real-or-random

Labels
user-documentation tweak/refactor