[D7] Allow modules to opt in to testing against max PHP version: OPT_IN_TEST_MAX_PHP

Issue information

From user: poker10

Related to !174 (merged) !173 (merged) !166 (merged)

Contribution record

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Problem/Motivation

This is a D7 backport of #3398709: Allow modules to opt in to testing against max PHP version: OPT_IN_TEST_MAX_PHP

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Proposed resolution

Remaining tasks

User interface changes

API changes

Data model changes