releng: Move the "performance" profile check inside the alltests plugin

releng: Move the "performance" profile check inside the alltests plugin

Right now, the alltests/pom.xml is used solely to run the
performance" profile, which runs the performance tests.

We can move the "if" inside the alltests plugin itself, so
that this pom.xml can be used for other profiles.

Change-Id: I7b03b1d5b1064b66e28226676849939fe2ca6975
Signed-off-by: Alexandre Montplaisir <alexmonthy@voxpopuli.im>
Reviewed-on: https://git.eclipse.org/r/51760
Reviewed-by: Hudson CI
Reviewed-by: Marc-Andre Laperle <marc-andre.laperle@ericsson.com>
Tested-by: Marc-Andre Laperle <marc-andre.laperle@ericsson.com>