Enabled background and reply time tracking on blocked on keys/blocked on background work clients (#7491)

This commit enables tracking time of the background tasks and on replies,
opening the door for properly tracking commands that rely on blocking / background
 work via the slowlog, latency history, and commandstats. 

Some notes:
- The time spent blocked waiting for key changes, or blocked on synchronous
  replication is not accounted for. 

- **This commit does not affect latency tracking of commands that are non-blocking
  or do not have background work.** ( meaning that it all stays the same with exception to
  `BZPOPMIN`,`BZPOPMAX`,`BRPOP`,`BLPOP`, etc... and module's commands that rely
  on background threads ). 

-  Specifically for latency history command we've added a new event class named
  `command-unblocking` that will enable latency monitoring on commands that spawn
  background threads to do the work.

- For blocking commands we're now considering the total time of a command as the
  time spent on call() + the time spent on replying when unblocked.

- For Modules commands that rely on background threads we're now considering the
  total time of a command as the time spent on call (main thread) + the time spent on
  the background thread ( if marked within `RedisModule_MeasureTimeStart()` and
  `RedisModule_MeasureTimeEnd()` ) + the time spent on replying (main thread)

To test for this feature we've added a `unit/moduleapi/blockonbackground` test that relies on
a module that blocks the client and sleeps on the background for a given time. 
- check blocked command that uses RedisModule_MeasureTimeStart() is tracking background time
- check blocked command that uses RedisModule_MeasureTimeStart() is tracking background time even in timeout
- check blocked command with multiple calls RedisModule_MeasureTimeStart()  is tracking the total background time
- check blocked command without calling RedisModule_MeasureTimeStart() is not reporting background time

1 files changed, 1 insertions, 0 deletions

diff --git a/runtest-moduleapi b/runtest-moduleapi
index 878b5c6ad..e554226c1 100755
--- a/runtest-moduleapi
+++ b/runtest-moduleapi
@@ -23,6 +23,7 @@ $TCLSH tests/test_helper.tcl \
 --single unit/moduleapi/hooks \
 --single unit/moduleapi/misc \
 --single unit/moduleapi/blockonkeys \
+--single unit/moduleapi/blockonbackground \
 --single unit/moduleapi/scan \
 --single unit/moduleapi/datatype \
 --single unit/moduleapi/auth \