How to reproduce:
1. Build the attached project for iOS
2. Build & Run the app to device via Xcode
3. Hold the "Repeat" button
4. Note that the log is only printed when the button is released

Actual result: GUI.RepeatButton returns true only when the button is released.
Expected result: GUI.RepeatButton returns true every frame it's pressed.

Devices reproducible with:
- iPhone 7 Plus (iOS 12.0)
- iPhone 7 (iOS 12.3.1)

Devices not reproducible with:
- VLNQA00054, Xiaomi MI 4LTE (MI 4LTE), Android 6.0.1, CPU: Snapdragon 801 MSM8974AC, GPU: Adreno (TM) 330

Reproducible with: 2018.4.6f1, 2018.4.10f1, 2019.2.7f2, 2019.3.0b5, 2020.1.0a6.
Regression introduced in: 2018.4.6f1.
Not reproducible with: 2018.4.5f1, 2018.3.14f1, 2017.4.32f1.

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Fixed in 2020.1.0a17, 2019.3.0f4, 2019.2.18f1, 2018.4.16f1.