[cling] Make parts of the cling codebase similar to upstream clang-repl

[devajithvs]

This Pull request:

Makes non-breaking changes to the existing code to make cling similar to upstream clang-repl. The idea is to make more changes in a similar fashion and completely swap out certain functions when they are similar enough.

Changes or fixes:

Checklist:

• tested changes locally
• updated the docs (if necessary)

This PR fixes #

[vgvassilev]

Thanks for taking up this challenge. This is awesome!

[vgvassilev]

@smuzaffar, we will probably start moving towards more upstream llvm parts in Cling. These PRs need to be tested on cmssw because of relocation and pcms. Can you test this PR?

[github-actions]

Test Results

    10 files      10 suites   2d 5h 48m 40s ⏱️
 2 631 tests  2 631 ✅ 0 💤 0 ❌
24 807 runs  24 807 ✅ 0 💤 0 ❌

Results for commit 244d744.

[smuzaffar]

@smuzaffar, we will probably start moving towards more upstream llvm parts in Cling. These PRs need to be tested on cmssw because of relocation and pcms. Can you test this PR?

CMSSW tests started via cms-sw#206

[smuzaffar]

@vgvassilev , cmssw tests looks good. A unit test failure is not related to this PR.

[vgvassilev]

@smuzaffar, thank you!

ROOT CI / mac14 ARM64 LLVM_ENABLE_ASSERTIONS=On seems to be broken at cmake configuration and I do not see how this could be caused by this PR. Let's move forward here.