S390: Guard RISBG usage with facility check

A use of risbg instruction is not guarded by the corresponding
GENERAL_INSTR_EXT facility check.  This will result in an illegal
instruction when running on hardware without that facility installed
(i.e. z9).

R=jyan@ca.ibm.com,michael_dawson@ca.ibm.com,mbrandy@us.ibm.com
BUG=

Review URL: https://codereview.chromium.org/1848533006

Cr-Commit-Position: refs/heads/master@{#35206}

src/crankshaft/s390/lithium-codegen-s390.cc

@@ -4229,7 +4229,8 @@ void LCodeGen::DoStoreKeyedFixedArray(LStoreKeyed* instr) {
     if (hinstr->key()->representation().IsSmi()) {
       __ SmiToPtrArrayOffset(scratch, key);
     } else {
-      if (instr->hydrogen()->IsDehoisted()) {
+      if (instr->hydrogen()->IsDehoisted() ||
+          !CpuFeatures::IsSupported(GENERAL_INSTR_EXT)) {
 #if V8_TARGET_ARCH_S390X
         // If array access is dehoisted, the key, being an int32, can contain
         // a negative value, as needs to be sign-extended to 64-bit for