unit-test: Use project defined b_lundef
unit-test: Use project defined b_lundef

The unit-test.py was setting b_lundef=false for address santinizer, and
setting b_lundef=true afterwards.

For a project generating shared library that invokes a function that is
implemented in other components, e.g. an OEM ipmi plugin, b_lundef=true
will cause the link failure with undefined reference.

For such projects, the meson.build will set b_lundef=false by default,
and the unit-test.py shall respect the project's setting or use the
default value, which is b_lundef=true.

Signed-off-by: Lei YU <fc52a17c06c071ee7cd115c972235443e2107013@bytedance.com>
Change-Id: I42a117819b18573dc47bfc4d807a65410bfbdde2

openbmc/openbmc-build-scripts,openbmc/openbmc-build-scripts