feat(mangler): mangle top level variables #24376

Job	Run time
Build Linter Benchmark	2m 46s
Benchmark (lexer)	1m 32s
Benchmark (parser)	2m 1s
Benchmark (transformer)	2m 4s
Benchmark (isolated_declarations)	1m 50s
Benchmark (semantic)	2m 1s
Benchmark (minifier)	2m 20s
Benchmark (codegen)	1m 59s
Benchmark linter (0)	3m 0s
Benchmark linter (1)	1m 31s
Upload benchmarks	16s
	21m 20s

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