RESCALE adding INEXACT_ROUND mode support and tests.

RESCALE with rounding mode of INEXACT_ROUND in ref model precise
mode when running a compliance test will return the minimum allowed
integer, and will also produce a bounds file with the maximum
allowed integer value so that compliance can be performed using
these two values as the range for the implementation.

Refactor RESCALE op to use common lambda function and fix scaling
checks.

Fix misspelling of Verfier in tosa_verify.
Rename abs_mode to bounds_mode in ref model.
Remove big endian flag from ref model internal config.

Signed-off-by: Jeremy Johnson <jeremy.johnson@arm.com>
Change-Id: I1ed22c4fbb0215ff5564db6e300e7c77dd405164