JIT: remove unused helpers

[EgorBo]

No description provided.

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Copilot review overview

🟢 Approval recommended

The removals are internally scoped, consistent across declarations and definitions, and have no remaining references.

Review effort: Balanced
Findings: None

What changed in this PR

Removes unused JIT helpers and disabled EH normalization code without changing active behavior.

Changes:

• Deletes unused floating-point, layout, bit-vector, scope, and code-generation helpers.
• Removes unused profile-synthesis modes.
• Simplifies EH normalization documentation and verification.

File	Description
utils.h	Removes unused floating-point declarations.
utils.cpp	Removes corresponding implementations.
layout.cpp	Removes unused numeric layout identifiers.
jiteh.cpp	Deletes disabled EH normalization case 3.
hashbv.h	Removes unused bit-vector APIs and freelist state.
hashbv.cpp	Removes their implementations.
fgprofilesynthesis.h	Removes unused synthesis options.
fgprofilesynthesis.cpp	Removes unused likelihood transformations.
compiler.h	Removes obsolete declarations.
compiler.cpp	Removes an unused scope-processing helper.
codegenlinear.cpp	Removes unused block-operation helpers.
codegencommon.cpp	Removes unused register push/pop helpers.
codegen.h	Removes corresponding declarations.

[EgorBo]

cc @dotnet/jit-contrib (should be 100% unused code), no diffs.

[EgorBo]

/ba-g #135031