tmf.all: use ITmfTimestamp#toNanos when possible

tmf.all: use ITmfTimestamp#toNanos when possible

The new helper replaces a longer line of

timestamp.normalize(0, ITmfTimestamp.NANO_SCALE).getValue()
with
timestamp.toNanos();

It also can run faster as it has a quick exit on a match of
scales, this saves an object allocation.

Change-Id: Ic3c307944082aef38be4525e4c2d3547237b6d88
Signed-off-by: Matthew Khouzam <matthew.khouzam@ericsson.com>
Reviewed-on: https://git.eclipse.org/r/67091
Reviewed-by: Hudson CI
Reviewed-by: Patrick Tasse <patrick.tasse@gmail.com>
Tested-by: Patrick Tasse <patrick.tasse@gmail.com>