[GR-69332] Return UNCAUGHT_EXCEPTION for uncaught exceptions.

PullRequest: graal/22095

Author: christianhaeubl

substratevm/src/com.oracle.svm.core/src/com/oracle/svm/core/graal/snippets/CEntryPointSnippets.java

@@ -716,7 +716,7 @@ private static int tearDownIsolate() {
             VMThreads.singleton().freeCurrentIsolateThread();
             return CEntryPointErrors.NO_ERROR;
         } catch (Throwable t) {
-            return reportException(t);
+            return CEntryPointErrors.UNCAUGHT_EXCEPTION;
         }
     }