java/openjdk17: fix build on powerpc64*

Backport the patch from openjdk19 to fix the recently appearing error:
/wrkdirs/usr/ports/java/openjdk17/work/jdk17u-jdk-17.0.9-9-1/src/hotspot/os_cpu/bsd_ppc/os_bsd_ppc.cpp:194:29: error: no member named 'is_safefetch_fault' in 'StubRoutines'
    if (pc && StubRoutines::is_safefetch_fault(pc)) {
              ~~~~~~~~~~~~~~^
/wrkdirs/usr/ports/java/openjdk17/work/jdk17u-jdk-17.0.9-9-1/src/hotspot/os_cpu/bsd_ppc/os_bsd_ppc.cpp:195:52: error: no member named 'continuation_for_safefetch_fault' in 'StubRoutines'
      os::Posix::ucontext_set_pc(uc, StubRoutines::continuation_for_safefetch_fault(pc));
                                     ~~~~~~~~~~~~~~^

java/openjdk17/files/patch-src_hotspot_os__cpu_bsd__ppc_os__bsd__ppc.cpp

@@ -0,0 +1,19 @@
+--- src/hotspot/os_cpu/bsd_ppc/os_bsd_ppc.cpp.orig	2022-12-21 16:54:47 UTC
++++ src/hotspot/os_cpu/bsd_ppc/os_bsd_ppc.cpp
+@@ -187,16 +187,6 @@ frame os::current_frame() {
+ bool PosixSignals::pd_hotspot_signal_handler(int sig, siginfo_t* info,
+                                              ucontext_t* uc, JavaThread* thread) {
+
+-  // Moved SafeFetch32 handling outside thread!=NULL conditional block to make
+-  // it work if no associated JavaThread object exists.
+-  if (uc) {
+-    address const pc = os::Posix::ucontext_get_pc(uc);
+-    if (pc && StubRoutines::is_safefetch_fault(pc)) {
+-      os::Posix::ucontext_set_pc(uc, StubRoutines::continuation_for_safefetch_fault(pc));
+-      return true;
+-    }
+-  }
+-
+   // decide if this trap can be handled by a stub
+   address stub = NULL;
+   address pc   = NULL;