fix(core/shell): speedup `Command.execute` & fix extra new lines #10068

Job	Run time
test (x86_64-pc-windows-msvc, windows-latest, 1.61.0, --no-default-features, no-default)	4m 35s
test (x86_64-pc-windows-msvc, windows-latest, 1.61.0, --features api-all, api-all)	8m 24s
test (x86_64-pc-windows-msvc, windows-latest, 1.61.0, --features tracing, all)	6m 59s
test (x86_64-unknown-linux-gnu, ubuntu-latest, 1.60.0, --no-default-features, no-default)	4m 0s
test (x86_64-unknown-linux-gnu, ubuntu-latest, 1.60.0, --features api-all, api-all)	6m 37s
test (x86_64-unknown-linux-gnu, ubuntu-latest, 1.60.0, --features tracing, all)	4m 1s
test (x86_64-apple-darwin, macos-13, 1.60.0, --no-default-features, no-default)	2m 29s
test (x86_64-apple-darwin, macos-13, 1.60.0, --features api-all, api-all)	3m 57s
test (x86_64-apple-darwin, macos-13, 1.60.0, --features tracing, all)	2m 36s
	43m 38s

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