[fusl] Add llvm's lit tool to third_party

third_party/lit/examples/many-tests/lit.cfg

+# -*- Python -*-
+
+from lit import Test
+
+class ManyTests(object):
+    def __init__(self, N=10000):
+        self.N = N
+
+    def getTestsInDirectory(self, testSuite, path_in_suite,
+                            litConfig, localConfig):
+        for i in range(self.N):
+            test_name = 'test-%04d' % (i,)
+            yield Test.Test(testSuite, path_in_suite + (test_name,),
+                            localConfig)
+
+    def execute(self, test, litConfig):
+        # Do a "non-trivial" amount of Python work.
+        sum = 0
+        for i in range(10000):
+            sum += i
+        return Test.PASS,''
+
+config.test_format = ManyTests()