test: Disable 60-math.c test.

* build-aux/check-mescc.sh (TESTS): Remove
lib/tests/scaffold/60-math.c.
(BROKEN_TESTS): Add it.

build-aux/check-mescc.sh

@@ -110,7 +110,6 @@ lib/tests/scaffold/51-pointer-sub.c
 lib/tests/scaffold/54-argc.c
 lib/tests/scaffold/54-argv.c
 lib/tests/scaffold/55-char-array.c
-lib/tests/scaffold/60-math.c
 lib/tests/scaffold/61-array.c
 lib/tests/scaffold/62-array.c
 lib/tests/scaffold/63-struct.c
@@ -275,6 +274,12 @@ lib/tests/string/90-snprintf.c
     fi
 fi
 
+# Tests that fail or pass nondeterministically
+BROKEN_TESTS="
+lib/tests/scaffold/60-math.c
+"
+
+
 recheck=${recheck-false}
 test_ext=.c
 log_compiler="${SHELL} ${srcdest}build-aux/test-c.sh"