Under the cover of the debugger transport layer, allocation on the
engine's heap has been made available to the public. As there are
actually no restrictions on what the allocated memory can be used
for, the memory management functions better fit in the core part
of the API.

Closes #1805

JerryScript-DCO-1.0-Signed-off-by: Akos Kiss akiss@inf.u-szeged.hu