use hard-coded table names for VALID_SIS_COLUMNS
use hard-coded table names for VALID_SIS_COLUMNS

This shaves about 0.8 seconds off canvas startup time in dev mode on my
MBP. Not a lot, but it's something.

Change-Id: I1e835e5a97a122b2f4a5c5dcd9d86d6a4c0369b0
Reviewed-on: https://gerrit.instructure.com/6472
Reviewed-by: Cody Cutrer <c4fe2b1d90ef8f2548c8aeabfa633434316f0305@instructure.com>
Tested-by: Hudson <dfb64870173313a9a7b56f814c8e3b33e268497a@instructure.com>

sdeleon28/canvas-lms,snehakachroo1/LSI_replica,va7map/canvas-lms,instructure/canvas-lms,landonwilkins/canvas-lms,sfu/canvas-lms,ShreniiNepal/shrenii_lmp,sdeleon28/canvas-lms,gbleydon/canvas-lms,arrivu/hoodemo,landonwilkins/canvas-lms,Unow/ins,ankithbti/canvas_lms,juoni/canvas-lms,ottenhoff/canvas-lms,fronteerio/canvas-lms,arrivu/arrivu-lms,wye0220/shindig-canvas,Unow/canvas-lms,jay3126/canvas-lms,dgynn/canvas-lms,wye0220/shindig-canvas,rup/Tarrax,leftplusrightllc/canvas-lms,wrdsb/canvas-lms,kyroskoh/canvas-lms,icelab/canvas,antoniuslin/canvas-lms,va7map/canvas-lms,greyhwndz/canvas-lms,venturehive/canvas-lms,usmschuck/canvas,HotChalk/canvas-lms,matematikk-mooc/canvas-lms,va7map/canvas-lms,loganrun/pincan,parbros/red-innovadores-lms,greyhwndz/canvas-lms,ankithbti/canvas_lms,wye0220/shindig-canvas,leftplusrightllc/canvas-lms,sfu/canvas-lms,narigone/canvas,tgroshon/canvas-lms,Jyaasa/canvas-lms,em2/canvas-lms,instructure/canvas-lms,gbleydon/canvas-lms,efrj/canvas-lms,instructure/canvas-lms,narigone/canvas,kyroskoh/canvas-lms,snehakachroo1/LSI_replica,roxolan/canvas-lms,wrdsb/canvas-lms,snehakachroo1/LSI_replica,rup/Tarrax,sdeleon28/canvas-lms,samuels410/greatlakes-lms,tgroshon/canvas-lms,Rvor/canvas-lms,roxolan/canvas-lms,utkarshx/canvas-lms,AndranikMarkosyan/lms,jay3126/canvas-lms,skmezanul/canvas-lms,arrivu/jigsaw-lms,Rvor/canvas-lms,efrj/canvas-lms,Unow/ins,Unow/canvas-lms,antoniuslin/canvas-lms,djbender/canvas-lms,SwinburneOnline/canvas-lms,skmezanul/canvas-lms,arrivu/jigsaw-lms,instructure/canvas-lms,arrivu/jigsaw-lms,juoni/canvas-lms,narigone/canvas,wimemx/Canvas,Jyaasa/canvas-lms,merichar/canvas-lms,parbros/red-innovadores-lms,SwinburneOnline/canvas-lms,grahamb/canvas-lms,usmschuck/canvas,venturehive/canvas-lms,efrj/canvas-lms,fronteerio/canvas-lms,greyhwndz/canvas-lms,arrivu/arrivu-lms,utkarshx/canvas-lms,merichar/canvas-lms,djbender/canvas-lms,utkarshx/canvas-lms,samuels410/greatlakes-lms,arrivu/qibla-ecampus,Jyaasa/canvas-lms,wrdsb/canvas-lms,nditech/red-innovadores-lms,redconfetti/canvas-lms,whalejasmine/canvas-lms,antoniuslin/canvas-lms,redconfetti/canvas-lms,HotChalk/canvas-lms,landonwilkins/canvas-lms,kyroskoh/canvas-lms,arrivu/hiring-site,ShreniiNepal/shrenii_lmp,em2/canvas-lms,ottenhoff/canvas-lms,leftplusrightllc/canvas-lms,djbender/canvas-lms,wrdsb/canvas-lms,eCNAP/CANVAS,Rvor/canvas-lms,roxolan/canvas-lms,arrivu/hoodemo,whalejasmine/canvas-lms,whalejasmine/canvas-lms,skmezanul/canvas-lms,loganrun/pincan,matematikk-mooc/canvas-lms,arrivu/qibla-ecampus,merichar/canvas-lms,em2/canvas-lms,SwinburneOnline/canvas-lms,redconfetti/canvas-lms,samuels410/greatlakes-lms,loganrun/pincan,djbender/canvas-lms,kyroskoh/canvas-lms,sfu/canvas-lms,matematikk-mooc/canvas-lms,shidao-fm/canvas-lms,snehakachroo1/LSI_replica,matematikk-mooc/canvas-lms,sli7246/canvas_branch,eCNAP/CANVAS,faraazkhan/canvas,whalejasmine/canvas-lms,icelab/canvas,grahamb/canvas-lms,roxolan/canvas-lms,parbros/red-innovadores-lms,venturehive/canvas-lms,faraazkhan/canvas,landonwilkins/canvas-lms,nditech/red-innovadores-lms,dgynn/canvas-lms,leftplusrightllc/canvas-lms,narigone/canvas,shidao-fm/canvas-lms,va7map/canvas-lms,Rvor/canvas-lms,grahamb/canvas-lms,utkarshx/canvas-lms,jay3126/canvas-lms,AndranikMarkosyan/lms,rup/Tarrax,grahamb/canvas-lms,instructure/canvas-lms,gbleydon/canvas-lms,wimemx/Canvas,AndranikMarkosyan/lms,tgroshon/canvas-lms,eCNAP/CANVAS,juoni/canvas-lms,usmschuck/canvas,arrivu/arrivu-lms,efrj/canvas-lms,antoniuslin/canvas-lms,ShreniiNepal/shrenii_lmp,instructure/canvas-lms,ankithbti/canvas_lms,juoni/canvas-lms,icelab/canvas,eCNAP/CANVAS,shidao-fm/canvas-lms,SwinburneOnline/canvas-lms,arrivu/hiring-site,skmezanul/canvas-lms,samuels410/greatlakes-lms,arrivu/hiring-site,sli7246/canvas_branch,dgynn/canvas-lms,Jyaasa/canvas-lms,nditech/red-innovadores-lms,wimemx/Canvas,greyhwndz/canvas-lms,redconfetti/canvas-lms,dgynn/canvas-lms,sdeleon28/canvas-lms,arrivu/hoodemo,nditech/red-innovadores-lms,faraazkhan/canvas,fronteerio/canvas-lms,HotChalk/canvas-lms,Unow/canvas-lms,ShreniiNepal/shrenii_lmp,sfu/canvas-lms,sfu/canvas-lms,usmschuck/canvas,tgroshon/canvas-lms,HotChalk/canvas-lms,fronteerio/canvas-lms,ottenhoff/canvas-lms,sli7246/canvas_branch,Unow/ins,jay3126/canvas-lms,shidao-fm/canvas-lms,grahamb/canvas-lms,sfu/canvas-lms,venturehive/canvas-lms,sfu/canvas-lms,arrivu/qibla-ecampus,instructure/canvas-lms,AndranikMarkosyan/lms