make previously broken macro being tested

As suggested by @joker-ehp, this commit undefines `__SHORTFILE__` in
`DebugLogTest.cpp` order to make the previously broken variant of
`DEBUGLOG_WITH_STREAM_AND_TYPE` being tested at least in this one test,
as it is otherwise never used in CI.

Signed-off-by: Ingo Müller <[email protected]>

Author: ingomueller-net

llvm/unittests/Support/DebugLogTest.cpp

@@ -6,6 +6,11 @@
 //
 //===----------------------------------------------------------------------===//
 
+// This macro is defined in the LLVM build system, but we undefine it here
+// so that we test at least once in-tree the case where __SHORT_FILE__ is not
+// defined.
+#undef __SHORT_FILE__
+
 #include "llvm/Support/DebugLog.h"
 #include "llvm/Support/raw_ostream.h"
 #include "gmock/gmock.h"