fix pathKey bug: uncached path maybe share the same pathKey, even after being cached in uiPath

Runtime/ui/painting/path.cs

             this._maxX = float.MinValue;
             this._maxY = float.MinValue;
 
-            if (this._cache != null) {
-                this._pathKey = pathGlobalKey++;
-                this._cache = null;
-            }
+            this._pathKey = pathGlobalKey++;
+            this._cache = null;
         }
 
         internal PathCache flatten(float scale) {
 
             this._commandx = x;
             this._commandy = y;
-            if (this._cache != null) {
-                this._pathKey = pathGlobalKey++;
-                this._cache = null;
-            }
+            
+            this._pathKey = pathGlobalKey++;
+            this._cache = null;
         }
 
         void _appendLineTo(float x, float y) {
 
             this._commandx = x;
             this._commandy = y;
-            if (this._cache != null) {
-                this._pathKey = pathGlobalKey++;
-                this._cache = null;
-            }
+            
+            this._pathKey = pathGlobalKey++;
+            this._cache = null;
         }
 
         void _appendBezierTo(float x1, float y1, float x2, float y2, float x3, float y3) {
             
             this._commandx = x3;
             this._commandy = y3;
-            if (this._cache != null) {
-                this._pathKey = pathGlobalKey++;
-                this._cache = null;
-            }
+            
+            this._pathKey = pathGlobalKey++;
+            this._cache = null;
+            
-            if (this._cache != null) {
-                this._pathKey = pathGlobalKey++;
-                this._cache = null;
-            }
+            this._cache = null;
+            
-            if (this._cache != null) {
-                this._pathKey = pathGlobalKey++;
-                this._cache = null;
-            }
+            this._cache = null;
         }
 
         public void relativeMoveTo(float x, float y) {