[ORC] Initialize native target in JITLinkRedirectionManagerTest test fixture.

The native target must be initialized here otherwise the test will be skipped
unless some prior test happens to initialize it. Failure to initialize the
native target was causing the test to be skipped when --gtest_filter was used.

Author: lhames

llvm/unittests/ExecutionEngine/Orc/JITLinkRedirectionManagerTest.cpp

@@ -26,6 +26,8 @@ class JITLinkRedirectionManagerTest : public testing::Test {
 
 protected:
   void SetUp() override {
+    OrcNativeTarget::initialize();
+
     auto JTMB = JITTargetMachineBuilder::detectHost();
     // Bail out if we can not detect the host.
     if (!JTMB) {