RFR: 8351156: C1: Remove FPU stack support after 32-bit x86 removal [v2]

[Vladimir Ivanov]

On Thu, 27 Mar 2025 20:07:32 GMT, Aleksey Shipilev <shade at openjdk.org> wrote:

> I think the intent for ShouldNotReachHere()-s in C1 code is to crash out on a gross error, instead of silently miscompiling.

It's not an universal convention and it varies even in `c1_LIRAssembler_x86.cpp`. 

For example, `LIR_Assembler::reg2mem` uses asserts for small dynamic dispatch tables while using `ShouldNotReachHere` on default case in top switch.

Anyway, it's a minor thing and more of a code style. 

If we want to crash on such conditions, `guarantee(cond, "")` looks superior to `if (cond) { ... } else { ShouldNotReachHere(); }`.

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PR Review Comment: https://git.openjdk.org/jdk/pull/24274#discussion_r2019108812