Support pure JVM JAR compilation and packaging for desktop JVM

[RanjithRagavan]

This PR adds support for compiling and packaging the ExecuTorch Java/Kotlin APIs as a standard JVM JAR package targeting desktop platforms (Linux, macOS, Windows). It resolves #16422 by decoupling the codebase from Android-specific APIs (using reflection to delegate android logging) and adding a new :executorch_jvm Gradle project. In addition, the JNI CMake configuration has been expanded to support building on desktop hosts.

cc @kirklandsign @cbilgin

[pytorch-bot]

🔗 Helpful Links

🧪 See artifacts and rendered test results at hud.pytorch.org/pr/pytorch/executorch/20761

• 📄 Preview Python docs built from this PR

Note: Links to docs will display an error until the docs builds have been completed.

❌ 5 New Failures, 1 Pending

As of commit adc3d15 with merge base b1ef9a5 ():

NEW FAILURES - The following jobs have failed:

• Lint / lintrunner (gh)
  >>> Lint for extension/android/CMakeLists.txt:
• pull / android / build-android (gh)
  Process completed with exit code 1.
• pull / unittest / linux / linux-job (gh)
  RuntimeError: Command docker exec -t 2fe6badb41a243a1d9e6ea416958fa68098b2734ba60bdd7fef847754d76cada /exec failed with exit code 1
• pull / unittest-editable / linux / linux-job (gh)
  RuntimeError: Command docker exec -t 3d2563e2746cbe204ef991a233b7bbab994911a1a9f57c19cd229b126e3db404 /exec failed with exit code 1
• pull / unittest-nxp-neutron / linux-job (gh)
  RuntimeError: Command docker exec -t 0579c02e368edec92268ec2b4e881eb968dd860201ce3ed16c6cf52599cb6c19 /exec failed with exit code 1

This comment was automatically generated by Dr. CI and updates every 15 minutes.

[RanjithRagavan]

@pytorchbot label "release notes: none"

[nil-is-all]

Hi @RanjithRagavan, thank you for the PR. Could you address the CI failures?