Do not pass DexFile to ClassLinker::Lookup/ResolveMethod().

The DexFile can be easily retrieved from the DexCache,
so reduce the number of arguments that need to be passed.

Test: m test-art-host-gtest
Test: testrunner.py --host --optimizing
Change-Id: I2e47280e7cb8b84595130c4abfb5ece18d7f5c75
diff --git a/runtime/class_linker-inl.h b/runtime/class_linker-inl.h
index 2d8d4b4..c086dd2 100644
--- a/runtime/class_linker-inl.h
+++ b/runtime/class_linker-inl.h
@@ -237,9 +237,7 @@
     StackHandleScope<2> hs(self);
     Handle<mirror::DexCache> h_dex_cache(hs.NewHandle(referrer->GetDexCache()));
     Handle<mirror::ClassLoader> h_class_loader(hs.NewHandle(declaring_class->GetClassLoader()));
-    const DexFile* dex_file = h_dex_cache->GetDexFile();
-    resolved_method = ResolveMethod<kResolveMode>(*dex_file,
-                                                  method_idx,
+    resolved_method = ResolveMethod<kResolveMode>(method_idx,
                                                   h_dex_cache,
                                                   h_class_loader,
                                                   referrer,