OpenJDK 9 and 10 may be removed once 11 is built.

Closes GH-8407

Build errors:

> * For target buildjdk_hotspot_variant-server_libjvm_objs_os_linux_ppc.o:
> /home/buildozer/aports/testing/openjdk11/src/jdk11u-jdk-11.0.4+4/src/hotspot/os_cpu/linux_ppc/os_linux_ppc.cpp:
> In function 'long unsigned int ucontext_get_trap(const ucontext_t*)':
> /home/buildozer/aports/testing/openjdk11/src/jdk11u-jdk-11.0.4+4/src/hotspot/os_cpu/linux_ppc/os_linux_ppc.cpp:154:30:
> error: 'void*' is not a pointer-to-object type
>    return uc->uc_mcontext.regs->trap;
                                 ^~

> * For target hotspot_variant-server_libjvm_objs_os_linux_ppc.o:
 /home/buildozer/aports/testing/openjdk11/src/jdk11u-jdk-11.0.4+4/src/hotspot/os_cpu/linux_ppc/os_linux_ppc.cpp:
 In function 'long unsigned int ucontext_get_trap(const ucontext_t*)':
> /home/buildozer/aports/testing/openjdk11/src/jdk11u-jdk-11.0.4+4/src/hotspot/os_cpu/linux_ppc/os_linux_ppc.cpp:154:30:
> error: 'void*' is not a pointer-to-object type
>    return uc->uc_mcontext.regs->trap;
>                               ^~

Ref: GH-7808

Closes GH-7808