java_tools with javac11 v4.0

• fixes bazelbuild/bazel#8614
• exposes a new toolchain //:prebuilt_toolchain which is using all the pre-built tools, including singlejar and ijar, even on remote execution. This toolchain should be used only when host and execution platform are the same, otherwise the binaries will not work on the execution platform.

To use this release add to your WORKSPACE file:

http_archive(
    name = "remote_java_tools_linux",
    sha256 = "96e223094a12c842a66db0bb7bb6866e88e26e678f045842911f9bd6b47161f5",
    urls = [
        "https://mirror.bazel.build/bazel_java_tools/releases/javac11/v4.0/java_tools_javac11_linux-v4.0.zip",
        "https://github.com/bazelbuild/java_tools/releases/download/javac11_v4.0/java_tools_javac11_linux-v4.0.zip",
    ],
)

http_archive(
    name = "remote_java_tools_windows",
    sha256 = "a1de51447b2ba2eab923d589ba6c72c289c16e6091e6a3bb3e67a05ef4ad200c",
    urls = [
        "https://mirror.bazel.build/bazel_java_tools/releases/javac11/v4.0/java_tools_javac11_windows-v4.0.zip",
        "https://github.com/bazelbuild/java_tools/releases/download/javac11_v4.0/java_tools_javac11_windows-v4.0.zip",
    ],
)

http_archive(
    name = "remote_java_tools_darwin",
    sha256 = "fbf5bf22e9aab9c622e4c8c59314a1eef5ea09eafc5672b4f3250dc0b971bbcc",
    urls = [
        "https://mirror.bazel.build/bazel_java_tools/releases/javac11/v4.0/java_tools_javac11_darwin-v4.0.zip",
        "https://github.com/bazelbuild/java_tools/releases/download/javac11_v4.0/java_tools_javac11_darwin-v4.0.zip",
    ],
)