core(tls): implement releasing of TLS on thread termination

- move TLS & instrumentation code out of core/utility.hpp
- (*) TLSData lost .gather() method (to dispose thread data on thread termination)
- use TLSDataAccumulator for reliable collecting of thread data
- prefer using of .detachData() + .cleanupDetachedData() instead of .gather() method

(*) API is broken: replace TLSData => TLSDataAccumulator if gather required
(objects disposal on threads termination is not available in accumulator mode)

modules/core/src/rand.cpp

@@ -770,7 +770,7 @@ void RNG::fill( InputOutputArray _mat, int disttype,
 
 cv::RNG& cv::theRNG()
 {
-    return getCoreTlsData().get()->rng;
+    return getCoreTlsData().rng;
 }
 
 void cv::setRNGSeed(int seed)