Merge #20218: test: Suppress epoll_ctl data race

fa949b3 test: Suppress epoll_ctl data race (MarcoFalke)

Pull request description:

  Happens intermittently: https://cirrus-ci.com/task/5462892373868544?command=ci#L5385

ACKs for top commit:
  hebasto:
    ACK fa949b3, I have reviewed the code and it looks OK, I agree it can be merged.

Tree-SHA512: d5aa559fc105053da594531722f2a03d898eadeb4413c3a728fc5116cc4d1a2c16c49649a24c75ea810e4ec6bb9728b0bcd2ea991886bb9d206170218eddf6d2

test/sanitizer_suppressions/tsan

@@ -47,3 +47,4 @@ deadlock:src/qt/test/*
 # External libraries
 deadlock:libdb
 race:libzmq
+race:epoll_ctl  # https://github.com/bitcoin/bitcoin/pull/20218