perf: cranelift-codegen-meta: optimize llvm-lines in fmtln! Formatter

[dishmaker]

-3.6% less llvm-lines

Before:

Lines                 Copies              Function name
  -----                 ------              -------------
  192891                4360                (TOTAL)
   10042 (5.2%,  5.2%)     1 (0.0%,  0.0%)  cranelift_codegen_meta[b743bf4194d43139]::shared::instructions::define
    3772 (2.0%,  7.2%)     1 (0.0%,  0.0%)  <cranelift_codegen_meta[b743bf4194d43139]::gen_isle::NumericOp>::ops_for_type
    2301 (1.2%,  8.4%)     1 (0.0%,  0.1%)  cranelift_codegen_meta[b743bf4194d43139]::gen_isle::gen_numerics_isle
    2012 (1.0%,  9.4%)     1 (0.0%,  0.1%)  cranelift_codegen_meta[b743bf4194d43139]::isle::get_isle_compilations
    1510 (0.8%, 10.2%)     1 (0.0%,  0.1%)  cranelift_codegen_meta[b743bf4194d43139]::isa::x86::define
    1276 (0.7%, 10.8%)     1 (0.0%,  0.1%)  cranelift_codegen_meta[b743bf4194d43139]::gen_isle::gen_common_isle
    1150 (0.6%, 11.4%)     1 (0.0%,  0.2%)  cranelift_codegen_meta[b743bf4194d43139]::gen_asm::generate_macro_inst_fn::{closure#3}
     990 (0.5%, 12.0%)     1 (0.0%,  0.2%)  alloc[24b8200b0946867]::str::join_generic_copy::<str, u8, &str>
     958 (0.5%, 12.4%)     1 (0.0%,  0.2%)  cranelift_codegen_meta[b743bf4194d43139]::gen_asm::generate_isle
     870 (0.5%, 12.9%)     1 (0.0%,  0.2%)  cranelift_codegen_meta[b743bf4194d43139]::isa::riscv64::define
     855 (0.4%, 13.3%)     1 (0.0%,  0.3%)  cranelift_codegen_meta[b743bf4194d43139]::shared::instructions::define_control_flow
     853 (0.4%, 13.8%)     1 (0.0%,  0.3%)  cranelift_codegen_meta[b743bf4194d43139]::pulley::generate_isle

After:

 Lines                 Copies              Function name
  -----                 ------              -------------
  185944                4361                (TOTAL)
   10042 (5.4%,  5.4%)     1 (0.0%,  0.0%)  cranelift_codegen_meta[b743bf4194d43139]::shared::instructions::define
    3772 (2.0%,  7.4%)     1 (0.0%,  0.0%)  <cranelift_codegen_meta[b743bf4194d43139]::gen_isle::NumericOp>::ops_for_type
    2012 (1.1%,  8.5%)     1 (0.0%,  0.1%)  cranelift_codegen_meta[b743bf4194d43139]::isle::get_isle_compilations
    1510 (0.8%,  9.3%)     1 (0.0%,  0.1%)  cranelift_codegen_meta[b743bf4194d43139]::isa::x86::define
    1301 (0.7%, 10.0%)     1 (0.0%,  0.1%)  cranelift_codegen_meta[b743bf4194d43139]::gen_isle::gen_numerics_isle
     990 (0.5%, 10.6%)     1 (0.0%,  0.1%)  alloc[24b8200b0946867]::str::join_generic_copy::<str, u8, &str>
     916 (0.5%, 11.0%)     1 (0.0%,  0.2%)  cranelift_codegen_meta[b743bf4194d43139]::gen_isle::gen_common_isle
     870 (0.5%, 11.5%)     1 (0.0%,  0.2%)  cranelift_codegen_meta[b743bf4194d43139]::isa::riscv64::define
     855 (0.5%, 12.0%)     1 (0.0%,  0.2%)  cranelift_codegen_meta[b743bf4194d43139]::shared::instructions::define_control_flow
     853 (0.5%, 12.4%)     1 (0.0%,  0.2%)  cranelift_codegen_meta[b743bf4194d43139]::pulley::generate_isle
     825 (0.4%, 12.9%)     1 (0.0%,  0.3%)  cranelift_codegen_meta[b743bf4194d43139]::gen_inst::gen_inst_builder
     810 (0.4%, 13.3%)     1 (0.0%,  0.3%)  cranelift_codegen_meta[b743bf4194d43139]::gen_asm::generate_macro_inst_fn::{closure#3}