libsanitizer: re-implement heap profiler.

libsanitizer: re-implement heap profiler.

In the previos heap profiler implementation HeapProfile instance was
created every time BackgroundThread wanted to collect statistical data.
This commit simply applies the singleton pattern: now there's only one
HeapProfile object which can both decide wether it's time to collect the
statistics and print profiling data.

Signed-off-by: Andrey Drobyshev <a.drobyshev@samsung.com>
Change-Id: I8dfa245d826c52749564346a2cd50788c5d91124