Added JUnit test cases for HTTPTokener

[surajdm123]

Context

This PR adds the missing unit test case for =HTTPTokener.

Test Plan

mvn -Dtest=HTTPTokenerTest test

...
[INFO] Running org.json.junit.HTTPTokenerTest
[INFO] Tests run: 9, Failures: 0, Errors: 0, Skipped: 0, Time elapsed: 0.040 s -- in org.json.junit.HTTPTokenerTest
[INFO] 
[INFO] Results:
[INFO] 
[INFO] Tests run: 9, Failures: 0, Errors: 0, Skipped: 0
[INFO] 
[INFO] ------------------------------------------------------------------------
[INFO] BUILD SUCCESS
[INFO] ------------------------------------------------------------------------

Next Steps

1. Add more missing test cases to make this codebase more resilient.

[sonarqubecloud]

Quality Gate passed

Issues
1 New issue
0 Accepted issues

Measures
0 Security Hotspots
0.0% Coverage on New Code
0.0% Duplication on New Code

See analysis details on SonarQube Cloud

[stleary]

What problem does this code solve?
Improves test coverage from 93% to 100% for HttpTokener

Does the code still compile with Java6?
Yes

Risks
Low

Changes to the API?
No

Will this require a new release?
No

Should the documentation be updated?
No

Does it break the unit tests?
No, this PR consists of new unit tests

Was any code refactored in this commit?
No

Review status
APPROVED

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