Java 17 toolchain support

[davido]

Description of the problem / feature request:

Support for java 17 to be used with toolchain resolution for java rules, e.g. with this section in .bazelrc:

# Builds using remote_jdk17, executes using remote_jdk17 or local_jdk
build:java17 --java_language_version=17
build:java17 --java_runtime_version=17
build:java17 --tool_java_language_version=17
build:java17 --tool_java_runtime_version=17

This build command should fetch remote JDK 17 and produce major java version 17:

  $ bazeldev build --config=java17 gerrit

Feature requests: what underlying problem are you trying to solve with this feature?

Build Java code and produce major java version 17.

According to JDK 17 release schedule: [1] the general availability will be available on
2021/09/14.

Bugs: what's the simplest, easiest way to reproduce this bug? Please provide a minimal example if possible.

  $ bazeldev build \
  --java_language_version=17 \
  --java_runtime_version=17 \
  --tool_java_language_version=17 \
  --tool_java_runtime_version=17 \
  gerrit

What operating system are you running Bazel on?

Linux.

What's the output of bazel info release?

Bazel@HEAD, Next major Bazel release (5.x) should include this feature.

[1] https://openjdk.java.net/projects/jdk/17

[cushon]

eb7bf8c

[asv]

Will this change be ported to the 4.x branch?