lttng: Move the UST memory analysis to use ILttngUstEventLayout

lttng: Move the UST memory analysis to use ILttngUstEventLayout

This will allow the analysis to work with different versions
of the UST.

Removed the getRequirements() test, because testing (what used
to be) statically-defined values is not particularly useful.

Fixes Bug: 470186.

Change-Id: Id3c80467a55c9c3d47c8073d49e8f4ea3ead4f5b
Signed-off-by: Alexandre Montplaisir <alexmonthy@voxpopuli.im>
Reviewed-on: https://git.eclipse.org/r/54272
Reviewed-by: Hudson CI
Reviewed-by: Marc-Andre Laperle <marc-andre.laperle@ericsson.com>
Tested-by: Marc-Andre Laperle <marc-andre.laperle@ericsson.com>