test: unskip tests that now pass on AIX

One skipped test remains, it creates very large Buffer objects,
triggering the AIX OOM to kill node and its parent processes.

See: nodejs/build#1849 (comment)

PR-URL: #29054
Reviewed-By: Colin Ihrig <cjihrig@gmail.com>
Reviewed-By: Luigi Pinca <luigipinca@gmail.com>
Reviewed-By: Rich Trott <rtrott@gmail.com>
Reviewed-By: Richard Lau <riclau@uk.ibm.com>

test/message/message.status

@@ -17,5 +17,3 @@ prefix message
 [$system==freebsd]
 
 [$system==aix]
-# https://github.com/nodejs/node/pull/28469
-vm_dont_display_syntax_error: SKIP

test/sequential/sequential.status

@@ -19,8 +19,7 @@ test-http2-large-file: PASS, FLAKY
 [$system==freebsd]
 
 [$system==aix]
-# https://github.com/nodejs/node/pull/28469
-test-async-wrap-getasyncid: SKIP
+# https://github.com/nodejs/node/pull/29054
 test-buffer-creation-regression: SKIP
 
 [$arch==arm]