Emit 1/0 and 0/0 instead of Infinity/NaN in enum transforms

[mehmet turac (mturac)]

Summary

Enum values that evaluate to Infinity, -Infinity, or NaN were emitted as bare identifier references. When a local variable shadows the global Infinity or NaN, the emitted code captures the wrong value at runtime.

This PR changes the emitter to produce numeric expressions (1/0, -(1/0), 0/0) instead, which evaluate to IEEE 754 positive infinity, negative infinity, and NaN regardless of any identifier shadowing.

Reproduction (from #55091)

const enum A { X = 1 / 0 }
{
  let Infinity = 3;
  console.log(A.X); // Before: emits `3` (captures local), After: emits `Infinity`
}

Changes

• tsc/internal/transformers/tstransforms/utilities.go — regular enum value emit
• tsc/internal/transformers/inliners/constenum.go — const enum inline emit
• Updated 3 existing baselines, added 1 new test case (enumInfinityShadowed.ts)

Both emit sites (regular enum transforms and const enum inlining) are fixed in the same way.

Risk

Low. The change is confined to the emit of non-finite numeric enum values. 1/0 and 0/0 are semantically identical to Infinity and NaN in JavaScript, just immune to shadowing. Declaration emit (.d.ts) is deliberately left unchanged since ambient contexts cannot shadow globals.

Fixes #55091

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[Ryan Cavanaugh (RyanCavanaugh)]

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