Arc: Remove unnecessary fmt::Display use for overflow assertion

[fereidani]

• I did not use an LLM to create a change in this PR.
• I used an LLM to create a change in this PR, and I have explained below how it was used.

This PR removes unnecessary fmt::Display generated assembly because of use of formatting in the overflow check assertion(assert!(n <= MAX_REFCOUNT, "{}", INTERNAL_OVERFLOW_ERROR);).

This reduces generated x64 assembly for counter increment(simplified) from:

increase_counter:
        test    rdi, rdi
        js      .LBB1_2
        inc     rdi
        mov     rax, rdi
        ret
.LBB1_2:
        sub     rsp, 24
        lea     rax, [rip + .Lanon.642d46026bcfa00bfed8baf8cdbf502d.2]
        mov     qword ptr [rsp + 8], rax
        lea     rax, [rip + <&str as core[4e7ceada952a6ea0]::fmt::Display>::fmt]
        mov     qword ptr [rsp + 16], rax
        lea     rdi, [rip + .Lanon.642d46026bcfa00bfed8baf8cdbf502d.0]
        lea     rdx, [rip + .Lanon.642d46026bcfa00bfed8baf8cdbf502d.4]
        lea     rsi, [rsp + 8]
        call    qword ptr [rip + core[4e7ceada952a6ea0]::panicking::panic_fmt@GOTPCREL]

.Lanon.642d46026bcfa00bfed8baf8cdbf502d.0:
        .asciz  "\300"

.Lanon.642d46026bcfa00bfed8baf8cdbf502d.1:
        .ascii  "Arc counter overflow"

To:

increase_counter:
        test    rdi, rdi
        js      .LBB0_2
        inc     rdi
        mov     rax, rdi
        ret
.LBB0_2:
        push    rax
        lea     rdi, [rip + .Lanon.642d46026bcfa00bfed8baf8cdbf502d.0]
        lea     rdx, [rip + .Lanon.642d46026bcfa00bfed8baf8cdbf502d.2]
        mov     esi, 41
        call    qword ptr [rip + core[4e7ceada952a6ea0]::panicking::panic_fmt@GOTPCREL]

.Lanon.642d46026bcfa00bfed8baf8cdbf502d.0:
        .ascii  "Arc counter overflow"

Godbolt link:
https://godbolt.org/z/3qjxooYWM

I expect bors to report a binary size reduction for all programs using Arc. There might also be performance improvements as a byproduct of CPU cache hit increase.

[rustbot]

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[panstromek]

@bors try @rust-timer queue

[rust-timer]

Awaiting bors try build completion.

@rustbot label: +S-waiting-on-perf

[rust-bors]

⌛ Trying commit 0ec97c2 with merge babfadb…

To cancel the try build, run the command @bors try cancel.

Workflow: https://github.com/rust-lang/rust/actions/runs/31240262676

[panstromek]

Note that I think we probably don't excercise this codepath very much in the compiler, so we probably won't see much impact in rustc-perf benchmarks. Are you trying to optimize something specific in the compiler or what's the reason you want to run perf on this?