Use arena for various function-scoped object types #103

Job	Run time
docker	1m 10s
thirdparty-tests (test_perl)	37m 49s
thirdparty-tests (test_cello)	24s
thirdparty-tests (test_curl)	10m 11s
thirdparty-tests (test_doom)	14s
thirdparty-tests (test_git)	18m 50s
thirdparty-tests (test_libpng)	2m 12s
thirdparty-tests (test_libuev)	1m 1s
thirdparty-tests (test_lua)	47s
thirdparty-tests (test_metalang99)	37s
thirdparty-tests (test_oniguruma_jq)	1m 0s
thirdparty-tests (test_openssh)	5m 2s
thirdparty-tests (test_openssl)	17m 40s
thirdparty-tests (test_php)	7m 7s
thirdparty-tests (test_postgres)	4m 58s
thirdparty-tests (test_python)	25m 51s
thirdparty-tests (test_qbe_hare)	32s
thirdparty-tests (test_sqlite)	4m 19s
thirdparty-tests (test_tinycc)	21s
thirdparty-tests (test_toxcore)	4m 47s
thirdparty-tests (test_toybox)	1m 2s
thirdparty-tests (test_vim)	2m 6s
thirdparty-tests (test_zlib)	24s
thirdparty-tests (test_zstd)	1m 32s
thirdparty-tests (build_gcc)	10m 51s
thirdparty-tests (build_musl)	1m 25s
thirdparty-tests (build_nano)	1m 4s
thirdparty-tests (build_sdl)	1m 48s
	2h 45m 4s

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