Add calendar constructor with timezone #560

Job	Run time
rust_ci (macos-latest, stable)	43s
rust_ci (macos-latest, beta)	52s
rust_ci (windows-latest, beta)	1m 41s
rust_ci (ubuntu-latest, nightly)	1m 46s
rust_ci (ubuntu-latest, stable)	56s
rust_ci (windows-latest, stable)	1m 47s
rust_ci (ubuntu-latest, beta)	1m 4s
rust_ci (windows-latest, nightly)	2m 38s
rust_ci (macos-latest, nightly)	1m 24s
	12m 51s

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