lib: refactor internal webidl converters #5996

Job	Run time
Build slim tarball	2m 7s
collect-openssl-versions	6s
x86_64-darwin: with shared libraries	34m 26s
aarch64-darwin: with shared libraries	27m 30s
aarch64-linux: Cache V8 build	4s
x86_64-linux: with shared libraries	30m 42s
aarch64-linux: with shared openssl_1_1 (1.1.1w)	26m 6s
aarch64-linux: with shared openssl_3_6 (3.6.1)	25m 35s
aarch64-linux: with shared openssl_4_0 (4.0.0)	26m 39s
aarch64-linux: with shared openssl_3_5 (3.5.5)	25m 55s
aarch64-linux: with shared openssl_3 (3.0.19)	25m 50s
	3h 45m 0s

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