Reproduction steps:

1. Open "Unity2019AndroidSystemIOFileWriteBug.zip" project
2. Build for Android
3. Check Logcat for "CachePath exists" and "Text file exists"
4. Notice "CachePath exists:" is "True"
5. Notice "Text file exists:" is "False"

Expected Result: "System.IO.File" "WriteAllBytes()" and "WriteAllText()" creates files and "Text file exists:" is "True"
Actual Result: "System.IO.File" "WriteAllBytes()" and "WriteAllText()" does not create files

Reproduced with: 2019.3.0a6, 2019.2.0b6, 2019.1.6f1, 2018.4.2f1, 2018.3.14f1, 2017.4.29f1

Repro Devices:
VLNQA00216, Razer Phone 2 (Phone 2), Android 8.1.0, CPU: Snapdragon 845 SDM845, GPU: Adreno (TM) 630
VLNQA00218, Samsung Galaxy Note9 (SM-N960U), Android 8.1.0, CPU: Snapdragon 845 SDM845, GPU: Adreno (TM) 630
VLNQA00124, Google Pixel 2 XL (Pixel 2 XL), Android 9, CPU: Snapdragon 835 MSM8998, GPU: Adreno (TM) 540
VLNQA00272, Samsung Galaxy S10+ (SM-G975U), Android 9, CPU: Snapdragon 855 SM8150, GPU: Adreno (TM) 640
VLNQA00115, Sony Xperia Z3 (D6603), Android 6.0.1, CPU: Snapdragon 801 MSM8974AC, GPU: Adreno (TM) 330
VLNQA00224, Samsung Galaxy A5(2017) (SM-A520F), Android 8.0.0, CPU: Exynos 7 Octa 7880, GPU: Mali-T830
VLNQA00098, Lge LG G4 (LG-H815), Android 6.0, CPU: Snapdragon 808 MSM8992, GPU: Adreno (TM) 418
VLNQA00109, Xiaomi MI NOTE Pro (MI NOTE Pro), Android 7.0, CPU: Snapdragon 810 MSM8994, GPU: Adreno (TM) 430
VLNQA00036, Motorola Moto G (1st Gen) (XT1032), Android 5.1, CPU: Snapdragon 400 MSM8226, GPU: Adreno (TM) 305
VLNQA00031, Lge Nexus 5 (Nexus 5), Android 6.0.1, CPU: Snapdragon 800 MSM8974, GPU: Adreno (TM) 330
VLNQA00002, Samsung Galaxy S5 Neo (SM-G903F), Android 6.0.1, CPU: Exynos 7 Octa 7580, GPU: Mali-T720