ReadAsyncTest.readOnlyTransaction is flaky

[olavloite]

Error:  Tests run: 10, Failures: 1, Errors: 0, Skipped: 0, Time elapsed: 0.152 s <<< FAILURE! -- in com.google.cloud.spanner.ReadAsyncTest
Error:  com.google.cloud.spanner.ReadAsyncTest.readOnlyTransaction -- Time elapsed: 0.051 s <<< FAILURE!
unexpected (1): v10
---
expected      : [v1, v2, v3, v10, v11, v12]
but was       : [v1, v2, v3, v10, v10, v11, v12]
	at com.google.cloud.spanner.ReadAsyncTest.readOnlyTransaction(ReadAsyncTest.java:326)

[olavloite]

Another flake:

Error:  Failures: 
Error:    ReadAsyncTest.readOnlyTransaction:326 unexpected (1): v10
---
expected      : [v1, v2, v3, v10, v11, v12]
but was       : [v1, v2, v3, v10, v10, v11, v12]