Implement DataOutputStream::writeUTF #550

Job	Run time
rust_ci (ubuntu-latest, nightly)	1m 44s
rust_ci (windows-latest, stable)	3m 15s
rust_ci (macos-latest, beta)	1m 3s
rust_ci (ubuntu-latest, beta)	1m 7s
rust_ci (macos-latest, nightly)	1m 35s
rust_ci (ubuntu-latest, stable)	1m 6s
rust_ci (windows-latest, beta)	1m 59s
rust_ci (macos-latest, stable)	58s
rust_ci (windows-latest, nightly)	2m 56s
	15m 43s

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