Update status of flaky windows vm tests

tests/lib/lib.status

Index: tests/lib/lib.status
diff --git a/tests/lib/lib.status b/tests/lib/lib.status
index 1ca6dcb2ebf9febb0916b2a4498bbcbfd7cdc4a8..b4f44651b80ff880a1085d872712bd8ed1775814 100644
--- a/tests/lib/lib.status
+++ b/tests/lib/lib.status
@@ -319,6 +319,9 @@ convert/utf85_test: Skip # Pass, Slow Issue 20111.
 [ $mode == debug && $arch == ia32 && $system == windows ]
 convert/streamed_conversion_json_utf8_decode_test: Skip  # Verification OOM.
 
+[ $runtime == vm && $mode == debug && $arch == x64 && $system == windows ]
+convert/streamed_conversion_json_utf8_decode_test: Pass, Slow
+
 [ $mode == debug && $arch != ia32 && $arch != x64 && $arch != simarm && $arch != simarmv5te ]
 convert/streamed_conversion_json_utf8_decode_test: Skip  # Verification not yet implemented.