test_fips: flush stdout before aborting on failure.

When running on a device via `adb shell`, stdout will be a pipe
and so is block buffered, leading to lost output if abort() is
called before flushing.

Change-Id: Ica67132fb8b2b1e7967df89fa3d0a9a793d8cbbf
Reviewed-on: https://boringssl-review.googlesource.com/c/boringssl/+/54025
Reviewed-by: Adam Langley <agl@google.com>
Reviewed-by: Bob Beck <bbe@google.com>
Commit-Queue: Bob Beck <bbe@google.com>
diff --git a/util/fipstools/test_fips.c b/util/fipstools/test_fips.c
index 42ed96b..ed95b8c 100644
--- a/util/fipstools/test_fips.c
+++ b/util/fipstools/test_fips.c
@@ -313,5 +313,6 @@
 
 err:
   printf("FAIL\n");
+  fflush(stdout);
   abort();
 }