Add SK_SUPPORT_LEGACY_HAIRLINE_END_CAP to work around dependent test failure.

BUG=skia:
GOLD_TRYBOT_URL= https://gold.skia.org/search?issue=2379843002

Review-Url: https://codereview.chromium.org/2379843002
diff --git a/public.bzl b/public.bzl
index 5cfd7d5..22753a7 100644
--- a/public.bzl
+++ b/public.bzl
@@ -601,6 +601,7 @@
     "SK_SUPPORT_LEGACY_ARITHMETICMODE",
     "SK_SUPPORT_LEGACY_COLORFILTER_PTR",
     "SK_SUPPORT_LEGACY_CREATESHADER_PTR",
+    "SK_SUPPORT_LEGACY_HAIRLINE_END_CAP",
     "SK_SUPPORT_LEGACY_IMAGEFACTORY",
     "SK_SUPPORT_LEGACY_IMAGEFILTER_PTR",
     "SK_SUPPORT_LEGACY_MASKFILTER_PTR",
diff --git a/src/core/SkScan_Hairline.cpp b/src/core/SkScan_Hairline.cpp
index ce3fe2b..cc57bb6 100644
--- a/src/core/SkScan_Hairline.cpp
+++ b/src/core/SkScan_Hairline.cpp
@@ -593,10 +593,12 @@
                 break;
         }
         if (SkPaint::kButt_Cap != capStyle) {
+#if !defined(SK_SUPPORT_LEGACY_HAIRLINE_END_CAP)
             if (prevVerb == SkPath::kMove_Verb &&
                     verb >= SkPath::kLine_Verb && verb <= SkPath::kCubic_Verb) {
                 firstPt = pts[0];  // the curve moved the initial point, so close to it instead
             }
+#endif
             prevVerb = verb;
         }
     }