[MathExtras] Remove unnecessary cast of a constant 1 in a subtract.
[MathExtras] Remove unnecessary cast of a constant 1 in a subtract.

Pretty sure this will automatically promoted to match the type of the other operand of the subtract. There's plenty of other similar code around here without this cast.

git-svn-id: 0ff597fd157e6f4fc38580e8d64ab130330d2411@309653 91177308-0d34-0410-b5e6-96231b3b80d8

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