[quickjs] Fix undefined flexible array member

This is a continuation of fxrev.dev/694821, that fixed
usage of quickjs in host tools, but evidently this is
also used on target where the roll of 694821 failed.

Bug: 103545
Change-Id: I4f7b5b1918089365109aa838314d762753403708

quickjs.c

diff --git a/quickjs.c b/quickjs.c
index 722fd58..c1d3cf4 100644
--- a/quickjs.c
+++ b/quickjs.c
@@ -2769,6 +2769,8 @@
             p->header.ref_count = 1;
             p->is_wide_char = str->is_wide_char;
             p->len = str->len;
+            void **dest = p->is_wide_char ? (void **)&p->u.str16 : (void **)&p->u.str8;
+            *dest = &p->str_storage;
 #ifdef DUMP_LEAKS
             list_add_tail(&p->link, &rt->string_list);
 #endif
@@ -3559,6 +3561,8 @@
     str = js_realloc2(s->ctx, s->str, sizeof(JSString) + (size << 1), &slack);
     if (!str)
         return string_buffer_set_error(s);
+    void **dest = s->is_wide_char ? (void **)&str->u.str16 : (void **)&str->u.str8;
+    *dest = &str->str_storage;
     size += slack >> 1;
     for(i = s->len; i-- > 0;) {
         str->u.str16[i] = str->u.str8[i];