feat!: remove built-ins polyfills on node >= 18 #57

Job	Run time
ʦ TypeScript (blob)	30s
ʦ TypeScript (file)	34s
ʦ TypeScript (fetch)	34s
ʦ TypeScript (stream)	31s
ʦ TypeScript (form-data)	36s
🧪 Test (file / ubuntu-latest / node@18)	44s
🧪 Test (fetch / windows-latest / node@18)	4m 29s
🧪 Test (file / windows-latest / node@18)	4m 21s
🧪 Test (fetch / macos-latest / node@18)	38s
🧪 Test (fetch / ubuntu-latest / node@20)	35s
🧪 Test (form-data / ubuntu-latest / node@18)	46s
🧪 Test (file / macos-latest / node@20)	53s
🧪 Test (fetch / macos-latest / node@20)	51s
🧪 Test (form-data / windows-latest / node@18)	3m 58s
🧪 Test (form-data / windows-latest / node@20)	3m 49s
🧪 Test (file / macos-latest / node@18)	1m 0s
🧪 Test (form-data / macos-latest / node@18)	35s
🧪 Test (fetch / ubuntu-latest / node@18)	39s
🧪 Test (file / windows-latest / node@20)	3m 26s
🧪 Test (form-data / macos-latest / node@20)	52s
🧪 Test (fetch / windows-latest / node@20)	4m 7s
🧪 Test (file / ubuntu-latest / node@20)	28s
🧪 Test (form-data / ubuntu-latest / node@20)	29s
	35m 25s

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