Merge `TraceLayout` into `TraceInfo` #950

Job	Run time
rustfmt	14s
Check with --all-features	24s
no-std (stable, wasm32-unknown-unknown)	33s
Clippy	25s
Check with --no-default-features	32s
no-std (nightly, wasm32-unknown-unknown)	38s
Test Rust stable on ubuntu	1m 14s
Test Rust nightly on ubuntu	1m 17s
	5m 17s

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