Add divide to Sk2x, use native vdiv and vsqrt on ARM 64.

src/core/Sk2x.h

Index: src/core/Sk2x.h
diff --git a/src/core/Sk2x.h b/src/core/Sk2x.h
index a64ad721a5f9aad5d812ff1ace5331c47b31b9ae..9b4e5ee61c7178433d974b8462711627d58c93aa 100644
--- a/src/core/Sk2x.h
+++ b/src/core/Sk2x.h
@@ -49,14 +49,17 @@ public:
     Sk2x      add(const Sk2x&) const;
     Sk2x subtract(const Sk2x&) const;
     Sk2x multiply(const Sk2x&) const;
+    Sk2x   divide(const Sk2x&) const;
 
     Sk2x operator +(const Sk2x& o) const { return this->add(o); }
     Sk2x operator -(const Sk2x& o) const { return this->subtract(o); }
     Sk2x operator *(const Sk2x& o) const { return this->multiply(o); }
+    Sk2x operator /(const Sk2x& o) const { return this->divide(o); }
 
     Sk2x& operator +=(const Sk2x& o) { return (*this = *this + o); }
     Sk2x& operator -=(const Sk2x& o) { return (*this = *this - o); }
     Sk2x& operator *=(const Sk2x& o) { return (*this = *this * o); }
+    Sk2x& operator /=(const Sk2x& o) { return (*this = *this / o); }
 
     Sk2x negate() const { return Sk2x((T)0) - *this; }
     Sk2x operator -() const { return this->negate(); }