Update to jdk-17.0.3.0+6 pre-release tarball (17usec.17.0.3+5-220408)
Add JDK-8284548 regression fix missing from pre-release tarball but in jdk-17.0.3+6/jdk-17.0.3-ga
Update release notes to 17.0.3.0+6
Add missing README.md and generate_source_tarball.sh
Introduce tests/tests.yml, based on the one in java-11-openjdk
JDK-8283911 patch no longer needed now we're GA
Switch to GA mode for release
** This tarball is embargoed until 2022-04-19 @ 1pm PT. **
Resolves: rhbz#2073575
