8055061: assert at share/vm/services/virtualMemoryTracker.cpp:332 Error: ShouldNotReachHere() when running NMT tests
Summary: Handled CDS mapping region and added test for the scenario
Reviewed-by: coleenp, ctornqvi

Summary: Refactored emptyStack to a static member of NativeCallStack, which is accessible in minimal build.
Reviewed-by: coleenp, dholmes

Summary: Dynamic allocate _reserved_regions instead of static object to avoid racing during process exit
Reviewed-by: dholmes, coleenp

Summary: Enhance scalability of native memory tracking
Reviewed-by: coleenp, ctornqvi, gtriantafill

Summary: Disallow increasing native memory tracking level
Reviewed-by: hseigel, ctornqvi, gtriantafill