LongVector HLK/ExecTest Improvements

[alsepkow]

• Discuss infrastructure for consuming input values. Ideally, we have something that can also be easily ingested in the offload test suite. We could generate values and a cpp or header file that defines all of the test arrays. That could be reformatted with a simple script for easy consumption by other tooling.

• Discuss the granularity level we want for these tests in the HLK. Right now there are entry points per intrinsic/data type. We could collapse this but then we lose granularity in the HLK. What happens if a particular test case fails? Do we lose coverage on the rest of that group if they aren't granular?

• Update shader code to use a cbuffer for the inputs

• Add the rest of the test cases for long vectors