lisa.utils: Fix destroyablecontextmanager exception handling
lisa.utils: Fix destroyablecontextmanager exception handling

FIX

Ensure exceptions are re-raised unless explicitly swallowed by the user
by returning a truthy value. This is necessary as the expected pattern
is to handle ContextManagerExit and not re-raise anything explicitly,
which would otherwise be necessary with a normal use of
contextlib.contextmanager.

ARM-software/lisa,ARM-software/lisa,ARM-software/lisa,ARM-software/lisa