test: mark some known flakes

PR-URL: nodejs#27193
Refs: nodejs#20750
Refs: nodejs#26610
Reviewed-By: Rich Trott <rtrott@gmail.com>
Reviewed-By: Richard Lau <riclau@uk.ibm.com>

test/parallel/parallel.status

@@ -16,6 +16,9 @@ test-worker-syntax-error: PASS,FLAKY
 test-worker-syntax-error-file: 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
+test-http2-client-upload-reject: PASS,FLAKY
 
 [$system==linux]
 
@@ -24,6 +27,8 @@ test-worker-memory: PASS,FLAKY
 [$arch==arm || $arch==arm64]
 # https://github.com/nodejs/node/issues/25028
 test-cli-node-options: PASS,FLAKY
+# https://github.com/nodejs/node/issues/26610
+test-async-hooks-http-parser-destroy: PASS,FLAKY
 
 [$system==solaris] # Also applies to SmartOS