Fix for fat stroked roundrects.
Fix for fat stroked roundrects.

The original method did not correctly compute the distance value along
the inner edge, so the antialiasing was not quite correct. This fixes
that by adding additional vertices and setting a different outerRadius.
GOLD_TRYBOT_URL= https://gold.skia.org/search?issue=2275423002

Review-Url: https://codereview.chromium.org/2275423002

rubenvb/skia,google/skia,HalCanary/skia-hc,google/skia,rubenvb/skia,HalCanary/skia-hc,HalCanary/skia-hc,aosp-mirror/platform_external_skia,aosp-mirror/platform_external_skia,HalCanary/skia-hc,google/skia,rubenvb/skia,aosp-mirror/platform_external_skia,Hikari-no-Tenshi/android_external_skia,google/skia,Hikari-no-Tenshi/android_external_skia,HalCanary/skia-hc,aosp-mirror/platform_external_skia,Hikari-no-Tenshi/android_external_skia,google/skia,aosp-mirror/platform_external_skia,google/skia,aosp-mirror/platform_external_skia,google/skia,rubenvb/skia,Hikari-no-Tenshi/android_external_skia,HalCanary/skia-hc,rubenvb/skia,Hikari-no-Tenshi/android_external_skia,aosp-mirror/platform_external_skia,google/skia,rubenvb/skia,aosp-mirror/platform_external_skia,Hikari-no-Tenshi/android_external_skia,rubenvb/skia,HalCanary/skia-hc,google/skia,HalCanary/skia-hc,rubenvb/skia,aosp-mirror/platform_external_skia,HalCanary/skia-hc,rubenvb/skia,Hikari-no-Tenshi/android_external_skia,HalCanary/skia-hc,rubenvb/skia,Hikari-no-Tenshi/android_external_skia,aosp-mirror/platform_external_skia,google/skia