[GR-73472] Add explicit null check and deopt in StaticObject.unwrap

PullRequest: graal/23301

Author: lkmcfj

espresso/src/com.oracle.truffle.espresso/src/com/oracle/truffle/espresso/runtime/staticobject/StaticObject.java

@@ -318,7 +318,12 @@ private Object getArray(EspressoLanguage language) {
     public final <T> T unwrap(EspressoLanguage language) {
         checkNotForeign();
         assert isArray();
-        return (T) getArray(language);
+        Object array = getArray(language);
+        if (array == null) {
+            CompilerDirectives.transferToInterpreterAndInvalidate();
+            throw EspressoError.shouldNotReachHere();
+        }
+        return (T) array;
     }
 
     public final <T> T get(EspressoLanguage language, int index) {