InformixDialect: add support for coalesce(), current_timestamp(), current_date()

Description

I've been extending and using for some time the InformixDialect to support the following functions: coalesce(), current_timestamp() and current_date():

Tested it with:
Informix Dynamic Server 11.70.UC7GE
IBM Informix JDBC Driver for IBM Informix Dynamic Server 4.10.JC5DE

Environment

Informix 11.70
JDBC Driver 4.10

Assignee

Vlad Mihalcea

Reporter

Gabriel Belingueres

Fix versions

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backPortable

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Suitable for new contributors

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Requires Release Note

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backportDecision

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Components

Affects versions

Priority

Minor
Configure