ReadAsyncTest.tableNotFound is flaky

[olavloite]

Error:  Tests run: 10, Failures: 1, Errors: 0, Skipped: 0, Time elapsed: 0.186 s <<< FAILURE! -- in com.google.cloud.spanner.ReadAsyncTest
Error:  com.google.cloud.spanner.ReadAsyncTest.tableNotFound -- Time elapsed: 0.069 s <<< FAILURE!
value of: getErrorCode()
expected: NOT_FOUND
but was : INTERNAL
	at com.google.cloud.spanner.ReadAsyncTest.tableNotFound(ReadAsyncTest.java:215)

https://github.com/googleapis/java-spanner/actions/runs/13325611289/job/37218092462?pr=3647

[olavloite]

Fixed in #3693