Remove a useless call: Calling lineVec.dot(qPts[0])

This is from https://github.com/google/skia/pull/9, an external pull
request from https://github.com/sylvestre.

BUG=skia:
R=bsalomon
GOLD_TRYBOT_URL= https://gold.skia.org/search?issue=2234563003

Review-Url: https://codereview.chromium.org/2234563003

src/gpu/GrPathUtils.cpp

@@ -249,7 +249,6 @@ void GrPathUtils::QuadUVMatrix::set(const SkPoint qPts[3]) {
             // distances to be to the left. This matches the non-degenerate
             // case.
             lineVec.setOrthog(lineVec, SkPoint::kLeft_Side);
-            lineVec.dot(qPts[0]);
             // first row
             fM[0] = 0;
             fM[1] = 0;