Update from https://crrev.com/309717

tools/valgrind/asan/third_party/asan_symbolize.py

Index: tools/valgrind/asan/third_party/asan_symbolize.py
diff --git a/tools/valgrind/asan/third_party/asan_symbolize.py b/tools/valgrind/asan/third_party/asan_symbolize.py
index 5fca136b695069ad16b5f2e9521c1c31a30030da..ffa57ee624e59333271e229efb0b905e496e11fb 100755
--- a/tools/valgrind/asan/third_party/asan_symbolize.py
+++ b/tools/valgrind/asan/third_party/asan_symbolize.py
@@ -366,12 +366,12 @@ class SymbolizationLoop(object):
     #  3. otherwise create a new symbolizer and pass all currently known
     #     .dSYM hints to it.
     if not binary in self.llvm_symbolizers:
-      use_last_symbolizer = True
+      use_new_symbolizer = True
       if self.system == 'Darwin' and self.dsym_hint_producer:
         dsym_hints_for_binary = set(self.dsym_hint_producer(binary))
-        use_last_symbolizer = bool(dsym_hints_for_binary - self.dsym_hints)
+        use_new_symbolizer = bool(dsym_hints_for_binary - self.dsym_hints)
         self.dsym_hints |= dsym_hints_for_binary
-      if self.last_llvm_symbolizer and use_last_symbolizer:
+      if self.last_llvm_symbolizer and not use_new_symbolizer:
           self.llvm_symbolizers[binary] = self.last_llvm_symbolizer
       else:
         self.last_llvm_symbolizer = LLVMSymbolizerFactory(