TMF: bug 440998: Set active task to null in TmfRequestExecutor when completed

This avoids keeping references to the request, which itself may contain
references to rather big objects.

Change-Id: Ib82fbea5cdc6b73a0a76d51bc2e960d0d223927a
Signed-off-by: Geneviève Bastien <gbastien+lttng@versatic.net>
TMF: Do not keep event matches by default when no processing unit is set

This reduces the memory footprint of even matching. Just counting the matches
is enough.

Change-Id: I7650fe55afc878b5afabf9b6cc0c9ec116026448
Signed-off-by: Geneviève Bastien <gbastien+lttng@versatic.net>

Conflicts:
	lttng/org.eclipse.linuxtools.tmf.core/src/org/eclipse/linuxtools/tmf/core/event/matching/TmfEventMatches.java
TMF: Fix trace synchronization memory performance test, to reduce variability

And document a bit more how to use the USED_JAVA_HEAP metric, so that it gives
accurate results.

Change-Id: Id776ab4cbd70f1f22bcfa9fc5efe95b97b6c4b77
Signed-off-by: Geneviève Bastien <gbastien+lttng@versatic.net>

Conflicts:
	lttng/org.eclipse.linuxtools.lttng2.kernel.core.tests/perf/org/eclipse/linuxtools/lttng2/kernel/core/tests/perf/event/matching/TraceSynchronizationBenchmark.java
Merge branch 'graph' of github.com:giraldeau/org.eclipse.linuxtools into graph

Signed-off-by: Francis Giraldeau <francis.giraldeau@gmail.com>

Conflicts:
	lttng/org.eclipse.linuxtools.lttng2.kernel.core.tests/perf/org/eclipse/linuxtools/lttng2/kernel/core/tests/perf/event/matching/TraceSynchronizationBenchmark.java
Completing the bench command

Signed-off-by: Francis Giraldeau <francis.giraldeau@gmail.com>
Refactor of pre-sync code

Move pre-sync code from tests to core package.

Signed-off-by: Francis Giraldeau <francis.giraldeau@gmail.com>
FIXME

Signed-off-by: Francis Giraldeau <francis.giraldeau@gmail.com>
Update read cli command

Signed-off-by: Francis Giraldeau <francis.giraldeau@gmail.com>