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>
diff --git a/lib/efi_selftest/Makefile b/lib/efi_selftest/Makefile
index e4d7542..4147018 100644
--- a/lib/efi_selftest/Makefile
+++ b/lib/efi_selftest/Makefile
@@ -45,6 +45,7 @@
 efi_selftest_textoutput.o \
 efi_selftest_tpl.o \
 efi_selftest_util.o \
+efi_selftest_variables_common.o \
 efi_selftest_variables.o \
 efi_selftest_variables_runtime.o \
 efi_selftest_watchdog.o