Java tools release with JDK 16 toolchain

This release is conducted from this PR: [1].

[1] bazelbuild/bazel#11514

Java tools release with JDK 14 toolchain

This release is conducted from this PR: [1].

[1] bazelbuild/bazel#11514

Release v12.1 with EP 2.5.1

This release contains error prone 2.5.1

Release with Error Prone 2.3.5-SNAPSHOT

This release includes demotion of several breaking checks from ERROR to WARN severity: [1].

Baseline is this EP commit: [2] and this Bazel commit: [3].

[1] google/error-prone#1620
[2] google/error-prone@8beaab4
[3] bazelbuild/bazel@bc74d1d

Release with Error Prone 2.3.4

Provide java tool with bumped Error Prone version to 2.3.4.