[SimpligyCFG] NFC intended, remove GCD that was only used for powers of two
[SimpligyCFG] NFC intended, remove GCD that was only used for powers of two

and replace with an equilivent countTrailingZeros.

GCD is much more expensive than this, with repeated division.

This depends on D60823

Differential Revision: https://reviews.llvm.org/D61151



git-svn-id: 0ff597fd157e6f4fc38580e8d64ab130330d2411@363422 91177308-0d34-0410-b5e6-96231b3b80d8

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