patch 9.0.2050: Vim9: crash with deferred function call and exception

Problem:  Vim9: crash with deferred function call and exception
Solution: Save and restore exception state

Crash when a deferred function is called after an exception and another
exception is thrown

closes: #13376
closes: #13377

Signed-off-by: Christian Brabandt <cb@256bit.org>
Co-authored-by: Yegappan Lakshmanan <yegappan@yahoo.com>
diff --git a/src/ex_eval.c b/src/ex_eval.c
index 68dc6d7..e319dee 100644
--- a/src/ex_eval.c
+++ b/src/ex_eval.c
@@ -748,6 +748,43 @@
 }
 
 /*
+ * Save the current exception state in "estate"
+ */
+    void
+exception_state_save(exception_state_T *estate)
+{
+    estate->estate_current_exception = current_exception;
+    estate->estate_did_throw = did_throw;
+    estate->estate_need_rethrow = need_rethrow;
+    estate->estate_trylevel = trylevel;
+}
+
+/*
+ * Restore the current exception state from "estate"
+ */
+    void
+exception_state_restore(exception_state_T *estate)
+{
+    if (current_exception == NULL)
+	current_exception = estate->estate_current_exception;
+    did_throw |= estate->estate_did_throw;
+    need_rethrow |= estate->estate_need_rethrow;
+    trylevel |= estate->estate_trylevel;
+}
+
+/*
+ * Clear the current exception state
+ */
+    void
+exception_state_clear(void)
+{
+    current_exception = NULL;
+    did_throw = FALSE;
+    need_rethrow = FALSE;
+    trylevel = 0;
+}
+
+/*
  * Flags specifying the message displayed by report_pending.
  */
 #define RP_MAKE		0