crypto/elliptic: change a variable name that have the same name as keywords

Change the variable name from byte to b, and use range over int to
simplify the loop.

Change-Id: I8855053c26ce798311f12505cd5edf21d7caf1f5
GitHub-Last-Rev: 70c8054
GitHub-Pull-Request: #74736
Reviewed-on: https://go-review.googlesource.com/c/go/+/690135
Reviewed-by: qiu laidongfeng <[email protected]>
LUCI-TryBot-Result: Go LUCI <[email protected]>
Reviewed-by: Roland Shoemaker <[email protected]>
Reviewed-by: Michael Knyszek <[email protected]>

Author: mohanson

src/crypto/elliptic/params.go

@@ -295,13 +295,13 @@ func (curve *CurveParams) ScalarMult(Bx, By *big.Int, k []byte) (*big.Int, *big.
 	Bz := new(big.Int).SetInt64(1)
 	x, y, z := new(big.Int), new(big.Int), new(big.Int)
 
-	for _, byte := range k {
-		for bitNum := 0; bitNum < 8; bitNum++ {
+	for _, b := range k {
+		for range 8 {
 			x, y, z = curve.doubleJacobian(x, y, z)
-			if byte&0x80 == 0x80 {
+			if b&0x80 == 0x80 {
 				x, y, z = curve.addJacobian(Bx, By, Bz, x, y, z)
 			}
-			byte <<= 1
+			b <<= 1
 		}
 	}