Replace getPOSIXTime with getMonotonicTimeNSec

[dancewithheart]

• use getMonotonicTimeNSec - Thank you @sol for spotting this!
• clean up time dependency
• getMonotonicTimeNSec is in base 4.11 and this is incompatible with GHC 8.8 so added conditional logic

Tested with toy example:

import Test.Framework.Utils
import Control.Concurrent (threadDelay)

main :: IO ()
main = do
  t0 <- getMicroTime
  threadDelay 10000
  t1 <- getMicroTime
  putStrLn $ "getMicroTime in micro sec = " <> show (t1 - t0)

  (_, elapsed) <- measure (threadDelay 10000)
  putStrLn $ "measure in mili sec = " <> show elapsed

that executed cabal exec -- runghc SmokeTest.hs produces:

getMicroTime in micro sec = 10412
measure in mili sec = 10

Similar numbers before change.