python: The new module has been removed in python3

python: The new module has been removed in python3

new.instance was used to instantiate a method bypassing the __init__
interface This patch is doing things properly by importing the LRTable
so that the LRParser interface is respected

Change-Id: I0b0ce184ef5ac297af40289a2896962c9a967a71
Signed-off-by: Giacomo Travaglini <giacomo.travaglini@arm.com>
Reviewed-on: https://gem5-review.googlesource.com/c/public/gem5/+/26243
Reviewed-by: Jason Lowe-Power <jason@lowepower.com>
Maintainer: Jason Lowe-Power <jason@lowepower.com>
Tested-by: kokoro <noreply+kokoro@google.com>