typechecker: some housekeeping in hhi files

Reviewed By: @jwatzman

Differential Revision: D1701098

Signature: t1:1701098:1416873058:f81c48c5748ea4ade05e3d2cbf9b004afea0420e
Silence "unsound type" warning

Summary: No idea why it doesn't know that `exit` is okay, and why it
shows up here and not on line 122, but w/e.

Fixes https://github.com/facebook/flow/issues/116

Reviewed By: @elgenie

Differential Revision: D1701802

Signature: t1:1701802:1416871970:eebc7d06d8a4203b6cd59637cc0648b3ae26d7fa
testrunner: remove automain mode

Summary: ... no longer necessary now that we jit pseudo-mains.

Reviewed By: @alexmalyshev

Differential Revision: D1702304

Signature: t1:1702304:1416879362:dd6f30749b96cf4a7a216a151f49b94bcb8a89fb
Updates to the relocation api

Summary: More changes needed for live code relocation

Reviewed By: @bertmaher

Differential Revision: D1699527

Signature: t1:1699527:1416864528:bf9653d5abed5fdeaf7f7d7a1fa4e193a5ff2bdd
Add extra stats recording to hack build

Summary: Record more information on CLIENT_BUILD_FINISH events

Reviewed By: @​jcreed

Differential Revision: D1702101

Signature: t1:1702101:1416933067:d916946c13238a2dc2114fa2fb85fa697018827a