tests/availability: fix resuming of suspended nodes

Resuming on test teardown is too late, doing it explicitly

tests/rptest/services/failure_injector.py

@@ -256,10 +256,11 @@ def _heal_all(self):
             if spec.type != FailureSpec.FAILURE_ISOLATE
         }
 
-    def _contunue_all(self):
+    def _continue_all(self):
         self.redpanda.logger.info(f"continuing execution on all nodes")
         for n in self.redpanda.nodes:
-            self._continue(n)
+            if self.redpanda.check_node(n):
+                self._continue(n)
         self._in_flight = {
             spec
             for spec in self._in_flight

tests/rptest/tests/availability_test.py

@@ -104,3 +104,5 @@ def test_recovery_after_catastrophic_failure(self):
         self.inject_failure(f_spec)
 
         self.validate_records()
+
+        self._continue_all()

tests/rptest/tests/e2e_finjector.py

@@ -90,6 +90,9 @@ def _failure_injector_loop(self):
                 f"waiting {delay} seconds before next failure")
             time.sleep(delay)
 
+    def _continue_all(self):
+        make_failure_injector(self.redpanda)._continue_all()
+
     def teardown(self):
         self.enable_failures = False
         if self.finjector_thread: