-C remark=... no longer emits optimization remarks

[tmiasko]

For example -Cremark=all for inflate rustc benchmark on 1.56 produces no output:

$ env RUSTFLAGS='-Copt-level=3 -Cdebuginfo=2 -Cremark=all -Awarnings' cargo +1.56 build --release
   Compiling inflate v0.1.0 (/tmp/inflate)
    Finished release [optimized] target(s) in 8.94s

Back in 1.24. the output used to look like:

$ env RUSTFLAGS='-Copt-level=3 -Cdebuginfo=2 -Cremark=all -Awarnings' cargo +1.24 build --release 
   Compiling inflate v0.1.0 (file:///tmp/inflate)
note: optimization remark for tailcallelim at /checkout/src/liballoc/raw_vec.rs:58:0: marked this call a tail call candidate

note: optimization remark for tailcallelim at /checkout/src/liballoc/raw_vec.rs:62:0: marked this call a tail call candidate

note: optimization analysis for inline at /checkout/src/liballoc/raw_vec.rs:121:0: _ZN49_$LT$alloc..raw_vec..RawVec$LT$T$C$$u20$A$GT$$GT$6new_in17h8bf74a74e147316dE can be inlined into _ZN40_$LT$alloc..raw_vec..RawVec$LT$T$GT$$GT$3new17h2ed8c5a26b1355fcE with cost=-14990 (threshold=412)

note: optimization remark for tailcallelim at /checkout/src/libcore/num/mod.rs:1:0: marked this call a tail call candidate

note: optimization analysis for inline at /checkout/src/libcore/num/mod.rs:2178:0: _ZN4core3num23_$LT$impl$u20$usize$GT$12wrapping_sub17h42e43db152cb00e3E can be inlined into _ZN4core3num23_$LT$impl$u20$usize$GT$15is_power_of_two17h4e167762c443022bE with cost=-35 (threshold=487)

...

<more output follows>