test: skip keygen tests on arm systems

test-crypto-keygen and test-crypto-dh-stateless are currently flaky
on ARM CI systems due to their slow CPUs.

PR-URL: nodejs#31178
Reviewed-By: Sam Roberts <vieuxtech@gmail.com>

test/parallel/parallel.status

@@ -33,6 +33,9 @@ test-worker-message-port-transfer-terminate: PASS,FLAKY
 [$arch==arm || $arch==arm64]
 # https://github.com/nodejs/node/issues/26610
 test-async-hooks-http-parser-destroy: PASS,FLAKY
+# https://github.com/nodejs/node/pull/31178
+test-crypto-dh-stateless: SKIP
+test-crypto-keygen: SKIP
 
 [$system==solaris] # Also applies to SmartOS