UI::PointInRectangle() takes up a large amount of CPU time when UI elements are touched.

Steps to reproduce:
1) Open the attached project.
2) Build for iOS.
3) In the built Xcode project, go to Build Settings > Build Options and set 'Debug Information Format' to 'DWARF with dSYM' file for all targets.
4) Deploy the project to a device.
5) Open Instruments with Time Profiler.
6) Run the build on target device via Instruments.
7) When the app launches, start holding fingers on UI elements on the device.
8) Pause execution in Instruments.
9) Take time sample with times, while the UI elements were used.
10) Expand the entry with largest 'Weight' fully.

Around 30% of total CPU time is spent in UI::PointInRectangle().
This happens with Mono2x and IL2CPP and across all graphics APIs.

Reproduced on:
2017.1.0b2, 5.6.0f1, 5.5.3p2

Tested on:
iPhone 7 Plus iOS 10.3.1
iPad Air 8.1.1