jamvm: bump to 2.0.0 (including mips big-endian support)

This commit bumps jamvm to version 2.0.0. From the release notes:

    I'm pleased to announce a new release of JamVM.  JamVM 2.0.0 is the
    first release of JamVM with support for OpenJDK (in addition to GNU
    Classpath). Although IcedTea already includes JamVM with OpenJDK
    support, this has been based on periodic snapshots of the development
    tree.

    JamVM 2.0.0 supports OpenJDK 6, 7 and 8 (the latest). With OpenJDK 7 and
    8 this includes full support for JSR 292 (invokedynamic). JamVM 2.0.0
    with OpenJDK 8 also includes full support for Lambda expressions (JSR
    335), type annotations (JSR 308) and method parameter reflection.

    In addition to OpenJDK support, JamVM 2.0.0 also includes many
    bug-fixes, performance improvements and improved compatibility (from
    running the OpenJDK jtreg tests).

As this release now also supports MIPS big-endian targets, this commit
fixes bug #7010 (https://bugs.busybox.net/show_bug.cgi?id=7010

)

Signed-off-by: Thomas De Schampheleire <thomas.de.schampheleire@gmail.com>
Signed-off-by: Peter Korsgaard <peter@korsgaard.com>