[flang] Remove macro replacement in angular bracket includes

Addresses Github issue [[ https://github.com/llvm/llvm-project/issues/60317 | #60317 ]].

Reviewed By: klausler

Differential Revision: https://reviews.llvm.org/D143469

flang/lib/Parser/preprocessor.cpp

@@ -599,7 +599,7 @@ void Preprocessor::Directive(const TokenSequence &dir, Prescanner &prescanner) {
             "#include: expected '>' at end of included file"_port_en_US);
       }
       TokenSequence braced{dir, j + 1, k - j - 1};
-      include = ReplaceMacros(braced, prescanner).ToString();
+      include = braced.ToString();
       j = k;
     } else if ((include = dir.TokenAt(j).ToString()).substr(0, 1) == "\"" &&
         include.substr(include.size() - 1, 1) == "\"") { // #include "foo"

flang/test/Preprocessing/preserve-brace-include.F90

@@ -0,0 +1,5 @@
+! RUN: %flang -E -I%S %s | FileCheck %s
+
+#define empty ERR_NONEXISTENT
+! CHECK-NOT: :5:
+#include <empty.h>