Remove questionable transform of Select from SelectStatic

[SolalPirelli]

Fixes #24707

This transform changed { x ; y }.v to { x ; y.v }.
But this is not valid if it's within an assignment, e.g., { x ; y }.v = 42 becoming the invalid { x ; y.v } = 42.

How much have you relied on LLM-based tools in this contribution?

not

How was the solution tested?

regression test from the issue

[som-snytt]

I'm motivated to learn, when I have a few minutes, why it's OK to revert the original code for the phase. I see it was to support the backend.

[SolalPirelli]

@som-snytt it seems based on git blame that the backend used to emit incorrect code in such cases. I guess this is a classic case of a "temporary" workaround.

[sjrd]

it seems based on git blame that the backend used to emit incorrect code in such cases. I guess this is a classic case of a "temporary" workaround.

If we suspect that the backend was producing bad code, we should have a run test to make sure the produced bytecode is validated by the JVM.

[SolalPirelli]

i1442 added by the original SelectStatic PR still passes, but it's true it's not the greatest coverage https://github.com/scala/scala3/pull/1445/changes

[SolalPirelli]

@sjrd I added a test