Fix Heap-buffer-overflow READ in opj_jp2_apply_pclr (#1441)

Fix Heap-buffer-overflow READ in opj_jp2_apply_pclr (#1441)

The issue was found while fuzzing opencv:
https://bugs.chromium.org/p/oss-fuzz/issues/detail?id=47342

The read overflow triggered by reading `src[j]` in
```cpp
            for (j = 0; j < max; ++j) {
                dst[j] = src[j];
            }
```
The max is calculated as `new_comps[pcol].w * new_comps[pcol].h`, however the `src = old_comps[cmp].data;` which may have different `w` and `h` dimensions.