Add test for duplicate definition of promise handles

Promise handles should allow the use of variables without triggering
duplicate handle errors
Methods that do nothing are also verified/kept

Fixes Redmine #4852. If a bundle invoked via a methods promise
results only in skipped promises, then the methods promise is kept.

That this issue exists with the test case in the redmine ticket
suggests that file promises return inconsistent results here. A
promise to create a file when that file exists should return NOOP,
not SKIPPED.
Redmine#4852: ensure a kept bundle is reported correctly to the methods promise
tests/acceptance/16_cf-serverd/01_start: re-enabled allow_path1_then_deny_path2*
Fix leak on failed mustache templates
Merge remote-tracking branch 'nick/redmine/4682'
Fix static handle duplicate checking

Do not count handles with variable references. Do not count duplicate handles
attached to promises with different class expressions.

Close #4682