Fix buffer overrun in DDM heap upload.

The HPSG heap upload was using a 4KB buffer.  A test provided by an
external developer is creating massive arrays that need more than 12KB,
so we overran the buffer and trashed the native heap.

This change adds a test to prevent the overrun, and increases the buffer
size to 16KB to accomodate the current maximum heap size.
1 file changed