[test] Avoid running crasher test cases on ASan

Author: hamishknight

validation-test/IDE/crashers/lit.local.cfg

@@ -1,2 +1,4 @@
 if "asserts" not in config.available_features:
     config.unsupported = True
+if "asan" in config.available_features:
+    config.unsupported = True

validation-test/compiler_crashers/lit.local.cfg

@@ -1,2 +1,4 @@
 if "asserts" not in config.available_features:
     config.unsupported = True
+if "asan" in config.available_features:
+    config.unsupported = True