test: mark SEA tests flaky on linux arm debug

The LIEF-based --build-sea tests can be killed by the OS on the
linux arm debug CI worker while rebuilding the ELF binary. The failures
all happen after SEA serialization succeeds, when the injector enters
LIEF::ELF::Builder::build(), and report SIGKILL instead of a test
assertion failure.

Mark the affected SEA build and application test families as flaky only
on linux arm debug, matching the node-test-commit-arm-debug job where
the flakes have been observed.

Signed-off-by: Kamat, Trivikram <16024985+trivikr@users.noreply.github.com>
PR-URL: #63743
Refs: https://github.com/nodejs/reliability/blob/main/reports/2026-06-10.md
Reviewed-By: Joyee Cheung <joyeec9h3@gmail.com>
Reviewed-By: Matteo Collina <matteo.collina@gmail.com>
Reviewed-By: Daijiro Wachi <daijiro.wachi@gmail.com>

Author: trivikr

test/sea/sea.status

@@ -20,6 +20,11 @@ test-build-sea*: SKIP
 test-single-executable-application*: SKIP
 test-build-sea*: SKIP
 
+[$system==linux && $arch==arm && $mode==debug]
+# https://github.com/nodejs/node/issues/63749
+test-single-executable-application*: PASS, FLAKY
+test-build-sea*: PASS, FLAKY
+
 [$system==win32]
 # https://github.com/nodejs/node/issues/49630
 test-single-executable-application-snapshot: PASS, FLAKY