[code-reflection] RFR: [hat] Float2 supported [v2]

[Juan Fumero]

> This PR adds `float2` in the API to generate 2 float instructions for OpenCL and CUDA backends. 
> 
> How to test?
> 
> 
> HAT=SHOW_CODE java -cp hat/job.jar hat.java test ffi-opencl hat.test.TestFloat2
> HAT=SHOW_CODE java -cp hat/job.jar hat.java test ffi-cuda hat.test.TestFloat2

Juan Fumero has updated the pull request with a new target base due to a merge or a rebase. The incremental webrev excludes the unrelated changes brought in by the merge/rebase. The pull request contains three additional commits since the last revision:

 - Merge branch 'code-reflection' into hat/vector/types
 - [hat] Add tests for float2 similar to float4
 - [hat] Adding float2 work

-------------

Changes:
  - all: https://git.openjdk.org/babylon/pull/666/files
  - new: https://git.openjdk.org/babylon/pull/666/files/c35619b7..88da10cb

Webrevs:
 - full: https://webrevs.openjdk.org/?repo=babylon&pr=666&range=01
 - incr: https://webrevs.openjdk.org/?repo=babylon&pr=666&range=00-01

  Stats: 3901 lines in 49 files changed: 206 ins; 3268 del; 427 mod
  Patch: https://git.openjdk.org/babylon/pull/666.diff
  Fetch: git fetch https://git.openjdk.org/babylon.git pull/666/head:pull/666

PR: https://git.openjdk.org/babylon/pull/666