Subzero: Fix off-by-one asserts in intrinsic info lookup routines.

It turns out that getNumArgs() and getReturnType() were never actually called except to print errors, so this bug was never encountered until now.

BUG= https://code.google.com/p/nativeclient/issues/detail?id=4315
R=ascull@google.com

Review URL: https://codereview.chromium.org/1347683002 .
2 files changed