[flang] Fix a test (use %s instead of $s)

With the typo ($S instead of %s), the driver was expecting
input from stdin. In such cases, it prints:
```
Enter Fortran source
Use EOF character (^D) to end file
```
This was piped to FileCheck. Together with the available `CHECK-NOT`
statement, this was sufficient for the test to pass (incorrectly).

This patch makes sure that the provided input file is used instead of
stdin.

Differential Revision: https://reviews.llvm.org/D100301

diff --git a/flang/test/Semantics/call17.f90 b/flang/test/Semantics/call17.f90
index ace6260..d392756 100644 (file)
--- a/flang/test/Semantics/call17.f90
+++ b/flang/test/Semantics/call17.f90
@@ -1,4 +1,4 @@
-! RUN: %f18 -fsyntax-only $s 2>&1 | FileCheck %s
+! RUN: %f18 -fsyntax-only %s 2>&1 | FileCheck %s --allow-empty
 
 ! Regression test: don't emit a bogus error about an invalid specification expression
 ! in the declaration of a binding