python: Add error for creating abstact SimObjects

Currently, if you try to instantiate an abstract SimObject the error is
confusing and unhelpful.

"TypeError: _m5.param_<type>.<type>Params: No constructor defined!"

Now, it will instead say "Cannot instantiate an abstract SimObject"
and include the name of the object that causes the error.

Change-Id: Ia8c51e29dccd999ec90dcd39710cc91d9a5fb86f
Signed-off-by: Jason Lowe-Power <jason@lowepower.com>
Reviewed-on: https://gem5-review.googlesource.com/c/public/gem5/+/59049
Reviewed-by: Andreas Sandberg <andreas.sandberg@arm.com>
Maintainer: Andreas Sandberg <andreas.sandberg@arm.com>
Tested-by: kokoro <noreply+kokoro@google.com>
1 file changed