Added RBE parameters to bazelrc, that will be needed once this version of Bazel is released. (RBE via bazel-toolchains is running using latest release bazel, in this case 3.7.2).

I updated bazel-toolchains repo, because it contains modifications that will be needed - detection of java version and generation of toolchains that are compatible with toolchain resolution.

I removed dummy_toolchain_reference, because the bug has apparently been fixed, and all tests pass without the workaround.

I removed special casing using EXECUTOR=remote for ijar and singlejar. This works with older version of Bazel on RBE, because execution constraints (os:windows/linux, cpu) were already properly detected.

Closes #12853.

PiperOrigin-RevId: 352574661