[clang-tools-extra] [clang] [clang][NFC] Refactor `CXXNewExpr::InitializationStyle` (PR #71322)

[Vlad Serebrennikov via cfe-commits]

Endilll wrote:

I've seen those exact test failures locally, but since precommit CI was fine, I landed this PR and kept a close eye on the bots.
Me and Aaron are also wondering now how did it pass CI, and what's wrong with changes here.
I'm sorry @zmodem that we got you involved.

> It catches (https://buildkite.com/llvm-project/github-pull-requests/builds/12931#018ba4b7-1e05-425f-a30d-46ac33f582b6), you just didn't wait for a results (or ignored them) and forced a merge.

Me and Aaron seen them, and deemed them unrelated. For a comparison, here is a list of tests that fails locally for me (and post-commit bots seem to agree):
```
Failed Tests (49):
  Clang :: Analysis/NewDelete-checker-test.cpp
  Clang :: Analysis/bstring.cpp
  Clang :: Analysis/cfg.cpp
  Clang :: Analysis/ctor-array.cpp
  Clang :: Analysis/cxxctr-array-evalcall-analysis-order.cpp
  Clang :: Analysis/dtor-array.cpp
  Clang :: Analysis/dump_egraph.cpp
  Clang :: Analysis/exploded-graph-rewriter/dynamic_types.cpp
  Clang :: Analysis/flexible-array-member.cpp
  Clang :: Analysis/handle_constructors_with_new_array.cpp
  Clang :: Analysis/more-dtors-cfg-output.cpp
  Clang :: Analysis/new-ctor-conservative.cpp
  Clang :: Analysis/new-ctor-inlined.cpp
  Clang :: Analysis/this-pointer.cpp
  Clang :: CXX/dcl.dcl/dcl.spec/dcl.constexpr/p9.cpp
  Clang :: CXX/drs/dr1748.cpp
  Clang :: CodeGen/available-externally-hidden.cpp
  Clang :: CodeGen/debug-prefix-map.cpp
  Clang :: CodeGen/split-lto-unit-input.cpp
  Clang :: CodeGen/tbaa-for-vptr.cpp
  Clang :: CodeGenCUDA/member-init.cu
  Clang :: CodeGenCXX/attr-disable-tail-calls.cpp
  Clang :: CodeGenCXX/catch-undef-behavior.cpp
  Clang :: CodeGenCXX/cfi-ms-vbase-derived-cast.cpp
  Clang :: CodeGenCXX/code-seg.cpp
  Clang :: CodeGenCXX/ctor-dtor-alias.cpp
  Clang :: CodeGenCXX/cxx1z-aligned-allocation.cpp
  Clang :: CodeGenCXX/cxx2a-destroying-delete.cpp
  Clang :: CodeGenCXX/default-arguments.cpp
  Clang :: CodeGenCXX/destructors.cpp
  Clang :: CodeGenCXX/exceptions.cpp
  Clang :: CodeGenCXX/invariant.group-for-vptrs.cpp
  Clang :: CodeGenCXX/key-function-vtable.cpp
  Clang :: CodeGenCXX/microsoft-abi-structors-delayed-template.cpp
  Clang :: CodeGenCXX/new-overflow.cpp
  Clang :: CodeGenCXX/new.cpp
  Clang :: CodeGenCXX/static-init.cpp
  Clang :: CodeGenCXX/strict-vtable-pointers.cpp
  Clang :: CodeGenCXX/type-metadata-thinlto.cpp
  Clang :: CodeGenCXX/ubsan-new-checks.cpp
  Clang :: CodeGenCXX/ubsan-suppress-checks.cpp
  Clang :: CodeGenCXX/vtable-assume-load-address-space.cpp
  Clang :: CodeGenCXX/vtable-assume-load.cpp
  Clang :: CodeGenCXX/vtable-available-externally.cpp
  Clang :: CodeGenObjCXX/arc-new-delete.mm
  Clang :: CodeGenObjCXX/destroy.mm
  Clang :: LibClang/symbols.test
  Clang :: SemaCXX/constant-expression-cxx2a.cpp
  Clang :: SemaCXX/constexpr-turing-cxx2a.cpp
```

https://github.com/llvm/llvm-project/pull/71322