minor code refactoring

Test: local
Change-Id: I7b9de2a4aa8d3d59ac3e5ec668e2b33e76bc003b
diff --git a/runners/host/base_test.py b/runners/host/base_test.py
index ff312e8..46a3da3 100644
--- a/runners/host/base_test.py
+++ b/runners/host/base_test.py
@@ -433,12 +433,10 @@
         if hasattr(self, keys.ConfigKeys.IKEY_ABI_BITNESS):
             bitness = getattr(self, keys.ConfigKeys.IKEY_ABI_BITNESS)
             asserts.skipIf(
-                (test_name[-len(const.SUFFIX_32BIT):].lower() ==
-                 const.SUFFIX_32BIT and bitness != "32") or
-                (test_name[-len(const.SUFFIX_64BIT):].lower() ==
-                 const.SUFFIX_64BIT and bitness != "64" and
-                 not getattr(self, keys.ConfigKeys.IKEY_RUN_32BIT_ON_64BIT_ABI,
-                             False)),
+                (test_name.lower().endswith(const.SUFFIX_32BIT) and
+                 self.abi_bitness != "32") or
+                (test_name.lower().endswith(const.SUFFIX_64BIT) and
+                 self.abi_bitness != "64" and not self.run_32bit_on_64bit_abi),
                 "Test case '{}' excluded as abi bitness is {}.".format(
                     test_name, bitness))