Update the toolchain to Fedora 33 with clang 11 (note the
build still uses gcc).
The image now creates a /root/.m2/repository directory; without
this the tools/jmx build fails on aarch64.
Add java-1.8.0-openjdk-devel since that is where javac lives now.
Add a JAVA8_HOME environment variable; wihtout this ant is not
able to find javac.
The toolchain is enabled for x86_64 and aarch64.