Fix non determinism and timezone dependency for issue#3158

What this PR does / why we need it

This PR fixes non-deterministic behavior in two specific files, ensuring consistent and reliable results across different builds. This resolves issue #3158

Summary of Changes

Modified Flaky Tests:
- MapTest.java:
- Updated test(), test1() and test2() to enforce a consistent ordering of map entries in the expected output, aligning it with the actual output format.
- DateTypeTest.java:
- Adjusted test() to correct the expected timestamp value, ensuring it matches the actual output. This was timezone dependent issue that is now fixed.

Testing Instructions

The changes can be validated using the NonDex plugin to simulate non-deterministic behavior:

mvn -pl codegen-test edu.illinois:nondex-maven-plugin:2.1.7:nondex -Dtest=com.alibaba.fastjson2.internal.processor.annotation.MapTest#test
mvn -pl codegen-test edu.illinois:nondex-maven-plugin:2.1.7:nondex -Dtest=com.alibaba.fastjson2.internal.processor.annotation.MapTest#test1
mvn -pl codegen-test edu.illinois:nondex-maven-plugin:2.1.7:nondex -Dtest=com.alibaba.fastjson2.internal.processor.annotation.MapTest#test2
mvn -pl codegen-test edu.illinois:nondex-maven-plugin:2.1.7:nondex -Dtest=com.alibaba.fastjson2.internal.processor.primitives.DateTypeTest#test

Checklist

[x] Ensured all tests are passing and test coverage is added where necessary.
[x] Verified that commit messages adhere to the Conventional Commits specification.
[x] Considered the documentation impact, and if needed, created or updated documentation accordingly.

Codecov Report

All modified and coverable lines are covered by tests :white_check_mark:

Project coverage is 74.22%. Comparing base (f6cdd54) to head (3701bf7). Report is 37 commits behind head on main.

Additional details and impacted files

```diff @@ Coverage Diff @@ ## main #3159 +/- ## ============================================ - Coverage 74.27% 74.22% -0.06% - Complexity 23542 23602 +60 ============================================ Files 659 668 +9 Lines 91870 92143 +273 Branches 20539 20602 +63 ============================================ + Hits 68238 68391 +153 - Misses 15240 15317 +77 - Partials 8392 8435 +43 ```

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alibaba / fastjson2