Add a GM for image filters applied to stroked primitives.
Add a GM for image filters applied to stroked primitives.

BUG=skia:3194

Review URL: https://codereview.chromium.org/1323573004

Hikari-no-Tenshi/android_external_skia,aosp-mirror/platform_external_skia,google/skia,google/skia,qrealka/skia-hc,google/skia,shahrzadmn/skia,HalCanary/skia-hc,qrealka/skia-hc,rubenvb/skia,tmpvar/skia.cc,google/skia,google/skia,aosp-mirror/platform_external_skia,HalCanary/skia-hc,rubenvb/skia,tmpvar/skia.cc,HalCanary/skia-hc,aosp-mirror/platform_external_skia,aosp-mirror/platform_external_skia,HalCanary/skia-hc,google/skia,shahrzadmn/skia,tmpvar/skia.cc,qrealka/skia-hc,HalCanary/skia-hc,google/skia,tmpvar/skia.cc,google/skia,aosp-mirror/platform_external_skia,shahrzadmn/skia,Hikari-no-Tenshi/android_external_skia,aosp-mirror/platform_external_skia,HalCanary/skia-hc,HalCanary/skia-hc,rubenvb/skia,aosp-mirror/platform_external_skia,Hikari-no-Tenshi/android_external_skia,Hikari-no-Tenshi/android_external_skia,Hikari-no-Tenshi/android_external_skia,shahrzadmn/skia,Hikari-no-Tenshi/android_external_skia,Hikari-no-Tenshi/android_external_skia,google/skia,aosp-mirror/platform_external_skia,HalCanary/skia-hc,qrealka/skia-hc,qrealka/skia-hc,shahrzadmn/skia,rubenvb/skia,Hikari-no-Tenshi/android_external_skia,rubenvb/skia,rubenvb/skia,tmpvar/skia.cc,aosp-mirror/platform_external_skia,shahrzadmn/skia,tmpvar/skia.cc,rubenvb/skia,qrealka/skia-hc,aosp-mirror/platform_external_skia,shahrzadmn/skia,shahrzadmn/skia,shahrzadmn/skia,qrealka/skia-hc,rubenvb/skia,HalCanary/skia-hc,qrealka/skia-hc,HalCanary/skia-hc,tmpvar/skia.cc,rubenvb/skia,google/skia,rubenvb/skia,tmpvar/skia.cc,tmpvar/skia.cc