build: Create single test binary xrpl_tests

[mathbunnyru]

High Level Overview of Change

Note: this doesn't change in any way integrated tests.
Instead of having multiple binaries we'll only have 1.
And we'll put this binary in the build directory and run it directly.
And we remove duplicated main.cpp files and link with gtest::gtest_main instead.

Also, we keep it possible to launch via ctest, but it discovers individulat gtest tests correctly now.

Context of Change

API Impact

• Public API: New feature (new methods and/or new fields)
• Public API: Breaking change (in general, breaking changes should only impact the next api_version)
• libxrpl change (any change that may affect libxrpl or dependents of libxrpl)
• Peer protocol change (must be backward compatible or bump the peer protocol version)

[Copilot]

Pull request overview

This PR consolidates the libxrpl gtest-based test suites into a single xrpl_tests binary while preserving CTest discovery for individual gtest cases.

Changes:

• Adds a shared xrpl_tests executable linked with GTest::gtest_main.
• Updates xrpl_add_test() to append sources and libraries to the shared test target.
• Removes duplicated per-module main.cpp files and runs xrpl_tests directly in CI.

Reviewed changes

Copilot reviewed 9 out of 9 changed files in this pull request and generated no comments.

Show a summary per file

File	Description
src/tests/libxrpl/CMakeLists.txt	Defines the combined test executable and wires all libxrpl test groups into it.
cmake/XrplAddTest.cmake	Changes the helper to append sources/libraries to xrpl_tests.
.github/workflows/reusable-build-test-config.yml	Runs the combined test binary directly in CI.
.gersemi/definitions.cmake	Updates formatter metadata for the new LIBRARIES argument.
src/tests/libxrpl/*/main.cpp	Removes duplicated gtest entry points now provided by gtest_main.

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[codecov]

Codecov Report

✅ All modified and coverable lines are covered by tests.
✅ Project coverage is 82.4%. Comparing base (f9551ac) to head (f5c3995).

Additional details and impacted files

@@            Coverage Diff            @@
##           develop   #7327     +/-   ##
=========================================
- Coverage     82.4%   82.4%   -0.0%     
=========================================
  Files         1011    1011             
  Lines        76477   76477             
  Branches      7326    7316     -10     
=========================================
- Hits         63004   62997      -7     
- Misses       13473   13480      +7     

see 11 files with indirect coverage changes

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[kuznetsss]

It is usually more convenient to have main file for tests in case we will need to do some global initialisation there. But I'm also ok to leave it as it is for now.

[mathbunnyru]

Good point, I added it :)

[kuznetsss]

Could you please explain, why do we still need xrpl_add_test()? Why couldn't we create one target executable with all the needed linked libraries and sources?

[mathbunnyru]

Because xrpl_add_test does isolate_headers, and it depends on the directory, so can't be done for a single target.

[github-actions]

This PR has conflicts, please resolve them in order for the PR to be reviewed.

[github-actions]

All conflicts have been resolved. Assigned reviewers can now start or resume their review.