only call scalar finite when necessary

src/pathops/SkPathOpsTSect.h

Index: src/pathops/SkPathOpsTSect.h
diff --git a/src/pathops/SkPathOpsTSect.h b/src/pathops/SkPathOpsTSect.h
index bebdf40208cb25b7997c594d3f6ca7c1a6be3c4a..074fe376549b1fd60bc4e4669c52d3ba3d23ab2f 100644
--- a/src/pathops/SkPathOpsTSect.h
+++ b/src/pathops/SkPathOpsTSect.h
@@ -1467,11 +1467,17 @@ int SkTSect<TCurve, OppCurve>::linesIntersect(SkTSpan<TCurve, OppCurve>* span,
         workT += tStep;
         workPt = fCurve.ptAtT(workT);
         coinW.setPerp(fCurve, workT, workPt, opp->fCurve);
+        if (coinW.perpT() < 0) {
+            continue;
+        }
         SkDVector perpW = workPt - coinW.perpPt();
         if ((perpS.dot(perpW) >= 0) == (tStep < 0)) {
             tStep = -tStep;
         }
-    } while (!workPt.approximatelyEqual(coinW.perpPt()));
+        if (workPt.approximatelyEqual(coinW.perpPt())) {
+            break;
+        }
+    } while (true);
     double oppTTest = coinW.perpT();
     if (!opp->fHead->contains(oppTTest)) {
         return 0;