test: add github refs to flaky tests

PR-URL: #28123
Reviewed-By: Richard Lau <riclau@uk.ibm.com>
Reviewed-By: Rich Trott <rtrott@gmail.com>
Reviewed-By: Beth Griggs <Bethany.Griggs@uk.ibm.com>
Reviewed-By: James M Snell <jasnell@gmail.com>
Reviewed-By: Colin Ihrig <cjihrig@gmail.com>

Author: sam-github

test/known_issues/known_issues.status

@@ -9,6 +9,8 @@ prefix known_issues
 [$system==win32]
 
 [$system==linux]
+# https://github.com/nodejs/node/pull/23743
+# https://github.com/nodejs/node/issues/3020
 test-vm-timeout-escape-promise: PASS,FLAKY
 
 [$system==macos]

test/parallel/parallel.status

@@ -11,11 +11,13 @@ test-net-connect-options-port: PASS,FLAKY
 test-worker-prof: PASS,FLAKY
 
 [$system==win32]
+# https://github.com/nodejs/node/issues/20750
 test-http2-pipe: PASS,FLAKY
 # https://github.com/nodejs/node/issues/23277
 test-worker-memory: PASS,FLAKY
 # https://github.com/nodejs/node/issues/20750
 test-http2-client-upload: PASS,FLAKY
+# https://github.com/nodejs/node/issues/20750
 test-http2-client-upload-reject: PASS,FLAKY
 # https://github.com/nodejs/node/issues/28106
 test-worker-debug: PASS,FLAKY