Update the spec reference testsuite submodule (#3450)

* Update the spec reference testsuite submodule

This commit brings in recent updates to the spec test suite. Most of the
changes here were already fixed in `wasmparser` with some tweaks to
esoteric modules, but Wasmtime also gets a bug fix where where import
matching for the size of tables/memories is based on the current runtime
size of the table/memory rather than the original type of the
table/memory. This means that during type matching the actual value is
consulted for its size rather than using the minimum size listed in its
type.

* Fix now-missing directories in build script

tests/misc_testsuite/many_table_gets_lead_to_gc.wast

@@ -0,0 +1,35 @@
+(module
+  (table $t 1 externref)
+
+  (func (export "init") (param externref)
+    (table.set $t (i32.const 0) (local.get 0))
+  )
+
+  (func (export "get-many-externrefs") (param $i i32)
+    (loop $continue
+      ;; Exit when our loop counter `$i` reaches zero.
+      (if (i32.eqz (local.get $i))
+        (return)
+      )
+
+      ;; Get an `externref` out of the table. This could cause the
+      ;; `VMExternRefActivationsTable`'s bump region to reach full capacity,
+      ;; which triggers a GC.
+      ;;
+      ;; Set the table element back into the table, just so that the element is
+      ;; still considered live at the time of the `table.get`, it ends up in the
+      ;; stack map, and we poke more of our GC bits.
+      (table.set $t (i32.const 0) (table.get $t (i32.const 0)))
+
+      ;; Decrement our loop counter `$i`.
+      (local.set $i (i32.sub (local.get $i) (i32.const 1)))
+
+      ;; Continue to the next loop iteration.
+      (br $continue)
+    )
+    unreachable
+  )
+)
+
+(invoke "init" (ref.extern 1))
+(invoke "get-many-externrefs" (i32.const 8192))