remove point aliases

This removes the notion of keeping track of every different t value
that resolves to the same or a similar point. Other fixes make
this concept unnecessary, and removing it simplifies the code.

This removes an allocation, and speeds up paths with many
overlapping curves.

As a bonus, four fuzzer tests that failed before now succeed.

TBR=reed@google.com
GOLD_TRYBOT_URL= https://gold.skia.org/search?issue=2275703003

Review-Url: https://codereview.chromium.org/2275703003
diff --git a/src/pathops/SkAddIntersections.cpp b/src/pathops/SkAddIntersections.cpp
index 1ca56b8..a6cebca 100644
--- a/src/pathops/SkAddIntersections.cpp
+++ b/src/pathops/SkAddIntersections.cpp
@@ -505,11 +505,9 @@
                 SkASSERT(ts[0][pt] >= 0 && ts[0][pt] <= 1);
                 SkASSERT(ts[1][pt] >= 0 && ts[1][pt] <= 1);
                 wt.segment()->debugValidate();
-                SkOpPtT* testTAt = wt.segment()->addT(ts[swap][pt], SkOpSegment::kAllowAliasMatch,
-                        nullptr);
+                SkOpPtT* testTAt = wt.segment()->addT(ts[swap][pt], nullptr);
                 wn.segment()->debugValidate();
-                SkOpPtT* nextTAt = wn.segment()->addT(ts[!swap][pt], SkOpSegment::kAllowAliasMatch,
-                        nullptr);
+                SkOpPtT* nextTAt = wn.segment()->addT(ts[!swap][pt], nullptr);
                 if (testTAt->addOpp(nextTAt)) {
                     testTAt->span()->checkForCollapsedCoincidence();
                 }