MUNMAP behavior for VM unbinds

• e.g. Two binds are done to 0x0000-0x2000 and 0x2000-0x4000 and single unbind is done to 0x1000-0x3000 which leaves us with mappings: 0x0000-0x1000 and 0x3000-0x4000

• e.g. Two binds are done to 0x0000-0x2000 and 0x3000-0x5000 and single unbind is done to 0x1000-0x4000 which leaves us with mappings: 0x0000-0x1000 and 0x4000-0x5000 (unbind are not an error if gaps in unbinds range)