fix the float Rect in OpenGLRenderer to handle NANs

- we want functions like isEmpty() to return true if NANs are
involved in the Rect

- also clean-up the intersect familly of calls

- minor cleanup in the int32_t Rect as well

These played a role in http://b/5331198.

Bug: 5331198

Change-Id: I5369725ab482e4b83da9f1bd4cee5256e5de75b2

include/ui/Rect.h

@@ -27,7 +27,7 @@ namespace android {
 class Rect : public ARect
 {
 public:
-    typedef int32_t value_type;
+    typedef ARect::value_type value_type;
 
     // we don't provide copy-ctor and operator= on purpose
     // because we want the compiler generated versions