[SPARK-4149][SQL] ISO 8601 support for json date time strings

[adrian-wang]

This implement the feature @davies mentioned in #2901 (diff)

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Test build #22518 has started for PR 3012 at commit c62b7e2.

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[SparkQA]

Test build #22518 has finished for PR 3012 at commit c62b7e2.

• This patch passes all tests.
• This patch merges cleanly.
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[davies]

Thanks for working on it. Can it infer the type as DateType/TimestampType from String in Json? It's common to have date/time in json, such as create time of tweet, it will be great if we access it as TimestampType.

[adrian-wang]

@davies I'd like to add auto detection in a separate PR.

[SparkQA]

Test build #23131 has started for PR 3012 at commit 50df6e7.

• This patch merges cleanly.

[SparkQA]

Test build #23131 has finished for PR 3012 at commit 50df6e7.

• This patch passes all tests.
• This patch merges cleanly.
• This patch adds no public classes.

[AmplabJenkins]

Test PASSed.
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https://amplab.cs.berkeley.edu/jenkins//job/SparkPullRequestBuilder/23131/
Test PASSed.

[marmbrus]

Thanks! Merged to master and 1.2