MLECO-4365: Add CI Test for insufficient tensor arena and update common tests.

Previously, execution path following failed tensor allocation
was not covered by tests.

Minor amendment added to make ~Model virtual.
During testing it was noticed that intentional errors simulated in
certain common tests would result in misleading output for subsequent tests
as the error messages appear in the console output of the next failing test.
Documentation and print statements added until a solution is found.

Change-Id: Iaf3e0f32ce9e0505921251cd41f73030108d2cb1
Signed-off-by: Liam Barry <liam.barry@arm.com>