package/openjdk{-bin}: drop OpenJDK11 and add OpenJDK21

package/openjdk{-bin}: drop OpenJDK11 and add OpenJDK21

OpenJDK 21 is out and with it, OpenJDK11 is now EOL.
See: https://endoflife.date/oracle-jdk As such, drop support for 11 and do the
following:

  - The 0001-Add-ARCv2-ISA-processors-support-to-Zero.patch patch now applies to
    both 17 and 21. Move it out of the version-specific directoriy.

  - BR2_OPENJDK_VERSION_LTS is now set to 17.

  - BR2_OPENJDK_VERSION_LATEST is now set to 21.

  - Drop --disable-hotspot-gtest as it has been removed, and was ignored in 17.

  - Add two separate HOST_OPENJDK_BIN_VERSION defines in openjdk-bin.mk as
    there is not a point release yet for OpenJDK 21.

  - Update the expectedVersion variable in JniTest.java from 0x000A0000 to
    0x00150000

Tested with:
./support/testing/run-tests tests.package.test_openjdk.TestOpenJdk.test_run

Signed-off-by: Adam Duskett <[email protected]>
Signed-off-by: Thomas Petazzoni <[email protected]>