Don't check permissions bits on init scripts for host_init_verifier

Also get rid of the copy in parser.  There's no incentive to switch to
a tokenizer that doesn't modify the input, nor is there a reason to
waste cycles making a copy of every init script as its processed.

Bug: 36970783
Test: boot
Change-Id: I8aca9c9d6f1961e1ab35dee50691a6791fc6ec66