FreeBSD (apparently) does not support crash-recovery tests.

These tests have been failing since the beginning of buildbot time:
crash-recovery-code-complete.c
crash-recovery-reparse.c
crash-recovery.c


git-svn-id: https://llvm.org/svn/llvm-project/cfe/trunk@138672 91177308-0d34-0410-b5e6-96231b3b80d8

test/lit.cfg

@@ -165,7 +165,10 @@ config.substitutions.append(
 ###
 
 # Set available features we allow tests to conditionalize on.
-config.available_features.add('crash-recovery')
+#
+# As of 2011.08, crash-recovery tests still do not pass on FreeBSD.
+if platform.system() not in ['FreeBSD']:
+    config.available_features.add('crash-recovery')
 
 # Shell execution
 if platform.system() not in ['Windows'] or lit.getBashPath() != '':