Fix Valgrind error in the test suite

[fktn-k]

This PR has fixed errors reported by Valgrind.
The errors were due to missing std::fclose() calls after opening a test data file in the input_adapter class test cases.
So no changes have been made to the library source codes.

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• Changes are described in the pull request or in a referenced issue.
• The test suite compiles and runs without any error.
• The code coverage on your branch is 100%.
• The documentation is updated if you added/changed a feature.

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[github-actions]

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ID	1398333619
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[coveralls]

Pull Request Test Coverage Report for Build 8618357114

Details

• 0 of 0 changed or added relevant lines in 0 files are covered.
• No unchanged relevant lines lost coverage.
• Overall coverage remained the same at 100.0%

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Totals
Change from base Build 8602833627:	0.0%
Covered Lines:	3464
Relevant Lines:	3464

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