use latest version of fastly/spidermonkey-wasi-embedding#12

Jake Champion · JakeChampion · commit 11eac9a6734d · 2023-04-11T15:15:03.000+01:00
diff --git a/c-dependencies/spidermonkey b/c-dependencies/spidermonkey
@@ -1 +1 @@
-Subproject commit a02a5db2961f81da347ec58c75bb8afad8d46af2
+Subproject commit 8b51b6f3add9171ef1878f0ede55a3719b6641e5
