Flaky test: TestNewAccountCanGoOnlineAndParticipate, TestOverlappingParticipationKeys, TestOnlineOfflineRewards

## Description
Travis Test Errors Reference Spreadsheet for details on cases where this test has failed: https://docs.google.com/spreadsheets/d/1apjaNvZodnTSIdZaQlpMaqf0nzbKgSYdIWHqvmINHS8/edit#gid=0

### Example Failure
Time: Wed 7/21/2021
Build: https://app.travis-ci.com/github/algorand/go-algorand/jobs/525817892#L1706
Travis Test: Ubuntu AMD64 Integration Test, MacOS AMD64 Integration Test
Package: test/e2e-go/features/participation
Test: TestNewAccountCanGoOnlineAndParticipate

Logs are long, so please reference the build link for more details.
```
=== Failed
=== FAIL: test/e2e-go/features/participation TestNewAccountCanGoOnlineAndParticipate (unknown)
=== FAIL: test/e2e-go/features/participation TestOverlappingParticipationKeys (unknown)
=== FAIL: test/e2e-go/features/participation TestOnlineOfflineRewards (unknown)
...
created by github.com/[secure]/go-deadlock.lock
algod(11830) : github.com/[secure]/go-deadlock@v0.2.1/deadlock.go:204 +0x136
algod(11830) : algod(11947) : Exiting on terminated
algod(11931) : Exiting on terminated
algod(11845) : Exiting on terminated
algod(11823) : Exiting on terminated
algod(11938) : Exiting on terminated
algod(11838) : Exiting on terminated
algod(11830) : Exiting on terminated
algod(11924) : Exiting on terminated
algod(11830) :
algod(11830) :
algod(11830) :
algod(11830) :
algod(11830) :
algod(11830) :
algod(11830) : panic: (*logrus.Entry) (0x1b4ea80,0xc0003375e0) [recovered]
algod(11830) : panic: (*logrus.Entry) (0x1b4ea80,0xc0003375e0)
algod(11830) : goroutine 23411 [running]:
algod(11830) : github.com/[secure]/go-[secure]/logging.logger.Panic.func1(0xc000198070, 0xc000010030)
algod(11830) : github.com/[secure]/go-[secure]/logging/log.go:252 +0xd5
algod(11830) : panic(0x1b4ea80, 0xc0003375e0)
algod(11830) : runtime/panic.go:975 +0x3e3
...
fixture.go:105:
Error Trace: participationRewards_test.go:50
participationRewards_test.go:104
Error: Received unexpected error:
fixture.WaitForRound took 218.09 seconds between round 13 and 14
Test: TestOnlineOfflineRewards
```