Use SSA-based GetRange for ArrLen in OptimizeRangeCheck

[EgorBo]

Closes #121682

Removes the bounds checks in ^

Diffs

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Pull Request Overview

This PR enhances the range check optimization by adding a fallback mechanism to determine array length using SSA-based analysis when assertion-based lookups fail. This enables removal of bounds checks in more scenarios, particularly for patterns involving index-from-end (^) operations.

Key Changes

• Adds SSA-based range analysis as a fallback when assertion-based array length lookup fails
• Uses the existing GetRangeWorker method to compute array length ranges when faster methods don't find a constant length

[hez2010]

Can you check does this also handle patterns like:

var buffer = new T[rows.Length];
var count = 0;
for (var i = 0; i < rows.Length; i++)
{
    if (predicate(rows[i])) buffer[count++] = rows[i]; // current there's bound check for buffer[count++]
}

[EgorBo]

Can you check does this also handle patterns like:

var buffer = new T[rows.Length];
var count = 0;
for (var i = 0; i < rows.Length; i++)
{
    if (predicate(rows[i])) buffer[count++] = rows[i]; // current there's bound check for buffer[count++]
}

it seems to be a different pattern, feel free to file an issue!

[AndyAyersMS]

it seems to be a different pattern, feel free to file an issue!

Seems like that case is already covered by #116238