feat(minifier): implement folding `charCodeAt` string fns #20866

Job	Run time
Build Linter Benchmark	2m 58s
Benchmark (lexer)	1m 29s
Benchmark (parser)	1m 40s
Benchmark (transformer)	2m 2s
Benchmark (isolated_declarations)	1m 56s
Benchmark (semantic)	1m 51s
Benchmark (minifier)	2m 35s
Benchmark (codegen)	1m 57s
Benchmark (sourcemap)	1m 40s
Benchmark linter (0)	3m 13s
Benchmark linter (1)	1m 36s
Upload benchmarks	18s
	23m 15s

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