Add test for function without an end marker. NFC

The function in this test end with a `drop` and is
otherwise well-formed but doesn't include the end
marker.

test/core/binary.wast

@@ -368,6 +368,25 @@
   "integer too large"
 )
 
+;; Function with missing end marker
+(assert_malformed
+  (module binary
+    "\00asm" "\01\00\00\00"
+    "\03\02\01\00"             ;; Function section
+    "\0a\06\02"                ;; Code section with 2 functions
+    ;; function 0
+    "\04\00"                   ;; Function size and local type count
+    "\41\01"                   ;; i32.const 1
+    "\1a"                      ;; drop
+    ;; Missing end marker here
+    ;; function 1
+    "\05\00"                   ;; Function size and local type count
+    "\41\01"                   ;; i32.const 1
+    "\1a"                      ;; drop
+    "\0b"                      ;; end
+  )
+  "END opcode expected"
+)
 
 ;; Unsigned LEB128 must not be overlong
 (assert_malformed