Fix heap testbed

Detail:
Kernel-5_44 tweaked the heap manager to try and avoid creating small
free blocks. Adjust HeapTest's block size checks so that it allows for
this behaviour.

Admin:
Tested briefly

Dev/HeapTest/c/testbed

@@ -421,7 +421,7 @@ int main(int argc,char **argv)
 					}
 					blocks[temp] = r.r[2]-((uint32_t)heap);
 					tryuse(blocks[temp]);
-					if((blocksize(blocks[temp])-(temp3+temp2)) > 7)
+					if((blocksize(blocks[temp])-(temp3+temp2)) > 11)
 					{
 						fprintf(stderr,"Failed to resize block by required amount: block %08x by %08x\n",blocks[temp],(int) temp2);
 						fail();