Fix a memory leak in SEQUENCE_free

Fixes check-src/check-135.-gen-OER.c and check-src/check64-136.-gen-OER.c

skeletons/constr_SEQUENCE.c

@@ -994,6 +994,9 @@ void
 SEQUENCE_free(const asn_TYPE_descriptor_t *td, void *sptr,
               enum asn_struct_free_method method) {
     size_t edx;
+    const asn_SEQUENCE_specifics_t *specs =
+        (const asn_SEQUENCE_specifics_t *)td->specifics;
+    asn_struct_ctx_t *ctx; /* Decoder context */
 
 	if(!td || !sptr)
 		return;
@@ -1013,6 +1016,10 @@ SEQUENCE_free(const asn_TYPE_descriptor_t *td, void *sptr,
 		}
 	}
 
+	/* Clean parsing context */
+	ctx = (asn_struct_ctx_t *)((char *)sptr + specs->ctx_offset);
+	FREEMEM(ctx->ptr);
+
     switch(method) {
     case ASFM_FREE_EVERYTHING:
         FREEMEM(sptr);