Merge `TraceLayout` into `TraceInfo` #947

Job	Run time
rustfmt	11s
Clippy	16s
Check with --all-features	30s
no-std (stable, wasm32-unknown-unknown)	31s
Check with --no-default-features	27s
no-std (nightly, wasm32-unknown-unknown)	44s
Test Rust stable on ubuntu	1m 10s
Test Rust nightly on ubuntu	1m 16s
	5m 5s

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