ts: test tags for flexible/reliable tests filtering

- added functionality to collect memory usage of OpenCL sybsystem
- memory usage of fastMalloc() (disabled by default):
  * It is not accurate sometimes - external memory profiler is required.
- specify common `CV_TEST_TAG_` macros
- added applyTestTag() function
- write memory usage / enabled tags into Google Tests output file (.xml)

platforms/scripts/valgrind.supp

@@ -19,6 +19,13 @@
    fun:_ZN2cv20allocSingletonBufferEm
 }
 
+{
+   OpenCV-SingletonNewBuffer
+   Memcheck:Leak
+   ...
+   fun:_ZN2cv23allocSingletonNewBufferEm
+}
+
 {
    OpenCV-getStdAllocator
    Memcheck:Leak