Provide a ScallocAssert that doesn't need any malloc() calls (unlike assert)

Signed-off-by: Michael Lippautz <michael.lippautz@gmail.com>
Add check for full arena.

Signed-off-by: Michael Lippautz <michael.lippautz@gmail.com>
Fixed medium size allocation.

Signed-off-by: Michael Lippautz <michael.lippautz@gmail.com>