Fixes <https://issues.guix.gnu.org/49990>.
Previously, building 'ant-bootstrap' would fail in obscure ways.
* gnu/packages/patches/classpath-miscompilation.patch: New file.
* gnu/local.mk (dist_patch_DATA): Add it.
* gnu/packages/java.scm (classpath-bootstrap)[source]: Use it.
[arguments]: Remove 'remove-call-to-free' phase.