Steps to reproduce:
1. Download 1130295_repro.zip and open "SampleScene"
2. Enter play mode

Expected results: Expectation is thrown one time and another async task loop isn't stopped.
Actual results: Exception is thrown multiple times and another async task loop is stopped.

Reproduced with: 2019.2.0a6, 2019.1.0b5, 2018.3.7f1
Not reproducible with: 2018.3.2f1, 2017.4.12f1
Regression introduced in: 2019.1.0a11, 2018.3.3f1

Exception: Exception of type 'System.Exception' was thrown.
NewBehaviourScript+<WaitAndThrowAsync>d__1.MoveNext () (at Assets/NewBehaviourScript.cs:22)
--- End of stack trace from previous location where exception was thrown ---
System.Runtime.ExceptionServices.ExceptionDispatchInfo.Throw () (at <3a07e6401b5d4cc98f7be596cb2130ba>:0)
System.Runtime.CompilerServices.AsyncMethodBuilderCore+<>c.<ThrowAsync>b__6_0 (System.Object state) (at <3a07e6401b5d4cc98f7be596cb2130ba>:0)
UnityEngine.UnitySynchronizationContext+WorkRequest.Invoke () (at C:/buildslave/unity/build/Runtime/Export/Scripting/UnitySynchronizationContext.cs:112)
UnityEngine.UnitySynchronizationContext.Exec () (at C:/buildslave/unity/build/Runtime/Export/Scripting/UnitySynchronizationContext.cs:73)
UnityEngine.UnitySynchronizationContext.ExecuteTasks () (at C:/buildslave/unity/build/Runtime/Export/Scripting/UnitySynchronizationContext.cs:94)