BF: Fix routine clock resetting in JS

[TEParsons]

When using nonslip timing, the nonslip duration was being subtracted from the routineTimer rather than the Clock (in Python these are one and the same, in JS the routineTimer is a CountdownTimer), meaning nonslip Routines were causing the following Routine to be skipped by messing up its timer.

It's also worth noting that Clock.add in JS works the opposite to Clock.addTime in Python - adding time to the clock reduces the value of getTime (as it adds the time to _lastResetTime)

[codecov]

Codecov Report

All modified and coverable lines are covered by tests ✅

Project coverage is 49.62%. Comparing base (eb5e61b) to head (3c6dbd9).
Report is 8 commits behind head on release.

Additional details and impacted files

@@             Coverage Diff             @@
##           release    #6861      +/-   ##
===========================================
- Coverage    49.64%   49.62%   -0.02%     
===========================================
  Files          332      332              
  Lines        61204    61204              
===========================================
- Hits         30383    30371      -12     
- Misses       30821    30833      +12     

Components	Coverage Δ
app	∅ <ø> (∅)
boilerplate	∅ <ø> (∅)
library	∅ <ø> (∅)
vm-safe library	∅ <ø> (∅)