Add -cost-model -analyze support to update_test_checks.py

[RKSimon]

Bugzilla Link	36907
Resolution	FIXED
Resolved on	Sep 25, 2020 11:56
Version	trunk
OS	Windows NT
Blocks	#35898
CC	@alexey-bataev,@adibiagio,@gregbedwell,@MaskRay,@rotateright
Fixed by commit(s)	329390

Extended Description

It'd be very useful if we could use update_test_checks.py to generate the cost model analysis checks for the likes of llvm\test\Analysis\CostModel\X86\arith.ll

[RKSimon]

rL329390 - added update_analyze_test_checks.py script instead of hacking update_test_checks.py