efi_selftest: add tests for QueryVariableInfo at runtime

Since we support QueryVariableInfo at runtime now add the relevant
tests. Since we want those to be reusable at bootime, add them
in a separate file

Add tests for
- Test QueryVariableInfo returns EFI_SUCCESS
- Test null pointers for the function arguments
- Test invalid combination of attributes

Signed-off-by: Ilias Apalodimas <ilias.apalodimas@linaro.org>

include/efi_selftest.h

@@ -147,6 +147,17 @@ void *efi_st_get_config_table(const efi_guid_t *guid);
  */
 u16 efi_st_get_key(void);
 
+/**
+ * efi_st_query_variable_common - Common variable tests for boottime/runtime
+ *
+ * @runtime:	Pointer to services table
+ * @attributes: Attributes used
+ *
+ * Return:	EFI_ST_SUCCESS/FAILURE
+ */
+int efi_st_query_variable_common(struct efi_runtime_services *runtime,
+				 u32 attributes);
+
 /**
  * struct efi_unit_test - EFI unit test
  *