Update some Sk4px APIs.

src/opts/SkNx_neon.h

Index: src/opts/SkNx_neon.h
diff --git a/src/opts/SkNx_neon.h b/src/opts/SkNx_neon.h
index 2087b8899bee6d68790eaa23e2b1d6d96874e5af..da926e0b4c2fafe57bba7b919e5d668e21ea6171 100644
--- a/src/opts/SkNx_neon.h
+++ b/src/opts/SkNx_neon.h
@@ -361,10 +361,6 @@ public:
 
     SkNi operator + (const SkNi& o) const { return vaddq_u8(fVec, o.fVec); }
     SkNi operator - (const SkNi& o) const { return vsubq_u8(fVec, o.fVec); }
-    SkNi operator * (const SkNi& o) const { return vmulq_u8(fVec, o.fVec); }
-
-    SkNi operator << (int bits) const { SHIFT8(vshlq_n_u8, fVec, bits); }
-    SkNi operator >> (int bits) const { SHIFT8(vshrq_n_u8, fVec, bits); }
 
     static SkNi Min(const SkNi& a, const SkNi& b) { return vminq_u8(a.fVec, b.fVec); }