build: commit Gradle wrapper, drop CI bootstrap step

[InbalHoni]

Motivation

The build currently provisions the Gradle wrapper at runtime via gradle -b bootstrap.gradle. This relies on Gradle APIs that are deprecated and removed in Gradle 9, and the step has become a source of CI failures. To decouple git-checkout and CI builds from the bootstrap step, this change commits the pinned Gradle 5.6.4 wrapper directly to the repository.

Changes

• Commit the Gradle wrapper (gradlew, gradlew.bat, gradle/wrapper/gradle-wrapper.jar, gradle/wrapper/gradle-wrapper.properties) and remove the corresponding .gitignore entries, so ./gradlew is available on a fresh checkout without bootstrapping.
• Remove the gradle -b bootstrap.gradle step from the tests and codeql-analysis workflows, which now invoke ./gradlew directly.

Source-release caveat

Per ASF policy, source-release tarballs must not contain binaries, so release.gradle continues to exclude the wrapper from the source release. The bootstrap path for source releases is therefore intentionally unchanged here. Aligning the source-release flow will be addressed in a future PR/release as part of upgrading the Gradle version.

Verification

Validated on a fork PR: both the tests and codeql-analysis workflows pass with the committed wrapper and no bootstrap step.

[eyala]

Thank you for your contribution!

The CI was disabled (because of the failures you are trying to fix). I re-enabled it, so if you could make some minor change (even the commit message) and repush, that should trigger it (I did see that it worked in your repository)

[InbalHoni]

Thank you for your contribution!

The CI was disabled (because of the failures you are trying to fix). I re-enabled it, so if you could make some minor change (even the commit message) and repush, that should trigger it (I did see that it worked in your repository)

Done.