Re #8359. Eliminate memory leaks in MRUList test.

It is the caller's responsibility to delete objects being dropped from the
MRU list, and that wasn't being done here before.
Re #8359. deleteIndex needs to also delete the pointed-to object.

I think. Certainly, this removes a memory leak in the MRUList unit test.
I will have to be guided by the other tests (including the system tests)
as to whether this is always the right thing to do. The method is only
directly used by the EventWorkspaceMRU class.
Re #8359. Clean up MRUList for readability.

Use auto to avoid long-winded declarations and remove unneeded local
variables and headers.
Re #8359. Clear memory leaks in ThreadSchedulerMutexesTest.
Re #8359. Clear memory leaks in UnitTest.
Re #8359. Fix memory leaks in Property unit test.
Re #8359. Clear memory leaks in DiskBufferTest.
Re #8359. Clear memory leaks in LogParserTest.
Re #8359. Clear memory leaks in TimeSeriesPropertyTest.
Re #8359. Clear memory leak in FilteredTimeSeriesProperty.

The class was incorrectly failing to delete the held TSP in the case
that ownership was not transferred, even though it took a clone of the
property and held onto that. This change means that the member variable
flag indicating ownership is no longer required.
Re #8359. Fix memory leak in FilteredTimeSeriesPropertyTest.
Re #8359. Avoid a memory leak when updateFacilities() is called.

It starts by clearing the list of facilities (which contains owned pointers
to FacilityInfo objects), but didn't delete the held objects.
Re #8359. Add suppression of a leak that's actually within Nexus.

It appears nexus gives a nice big leak if you try to open a file that isn't
an HDF file. There's nothing we can directly do about that.
Merge branch 'bugfix/8359_kernel_memory_leaks' into develop