perf(cubesql): Avoid allocations in MetaContext methods #4750

Job	Run time
Check fmt/clippy	3m 26s
Unit (Rewrite Engine) (CUBESQL_TOP_DOWN_EXTRACTOR=true)	6m 53s
Unit (Rewrite Engine) (CUBESQL_TOP_DOWN_EXTRACTOR=false)	7m 0s
Build macos-13 x86_64-apple-darwin 20.x with Python fallback	23m 47s
Build windows-2019 20.x with Python fallback	24m 37s
Build macos-13 aarch64-apple-darwin 20.x with Python fallback	20m 37s
Build Linux GNU 20.x x86_64-unknown-linux-gnu with Python 3.9	12m 47s
Build Linux GNU 20.x x86_64-unknown-linux-gnu with Python 3.10	11m 17s
Build Linux GNU 20.x x86_64-unknown-linux-gnu with Python 3.11	11m 15s
Build Linux GNU 20.x x86_64-unknown-linux-gnu with Python 3.12	11m 21s
Build Linux GNU 20.x x86_64-unknown-linux-gnu with Python fallback	11m 19s
Build Linux GNU 22.x x86_64-unknown-linux-gnu with Python 3.9	11m 22s
Build Linux GNU 22.x aarch64-unknown-linux-gnu with Python 3.9	11m 30s
Build Linux GNU 22.x x86_64-unknown-linux-gnu with Python 3.10	11m 19s
Build Linux GNU 22.x x86_64-unknown-linux-gnu with Python 3.11	11m 19s
Build Linux GNU 22.x x86_64-unknown-linux-gnu with Python 3.12	11m 23s
Build Linux GNU 22.x aarch64-unknown-linux-gnu with Python 3.12	11m 12s
Build Linux GNU 22.x x86_64-unknown-linux-gnu with Python fallback	11m 17s
Build Linux GNU 22.x aarch64-unknown-linux-gnu with Python fallback	10m 48s
	3h 54m 29s

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