Allow use of readonly_inputs for qemu_user template (#3116)

* Allow use of readonly_inputs for qemu_user template

* formatting fix

Author: Porges

src/cli/onefuzz/templates/libfuzzer.py

@@ -897,6 +897,7 @@ def qemu_user(
         no_check_fuzzer_help: bool = False,
         extra_container: Optional[Container] = None,
         crashes: Optional[Container] = None,
+        readonly_inputs: Optional[Container] = None,
     ) -> Optional[Job]:
         """
         libfuzzer tasks, wrapped via qemu-user (PREVIEW FEATURE)
@@ -950,7 +951,7 @@ def qemu_user(
         )
 
         if existing_inputs:
-            self.onefuzz.containers.get(existing_inputs)
+            self.onefuzz.containers.get(existing_inputs)  # ensure it exists
             helper.containers[ContainerType.inputs] = existing_inputs
         else:
             helper.define_containers(ContainerType.inputs)
@@ -968,6 +969,10 @@ def qemu_user(
         if extra_container is not None:
             fuzzer_containers.append((ContainerType.extra, extra_container))
 
+        if readonly_inputs is not None:
+            self.onefuzz.containers.get(readonly_inputs)  # ensure it exists
+            fuzzer_containers.append((ContainerType.readonly_inputs, readonly_inputs))
+
         helper.create_containers()
 
         target_exe_blob_name = helper.setup_relative_blob_name(target_exe, None)