Modernise code to use override specifier

Generated by clang-tidy, with IgnoreDestructors option enabled.

Test: m checkbuild
Bug: 116509795
Change-Id: I5dafa10c2cf605165581b8cf7dd2633ed101ed65
diff --git a/dex2oat/linker/image_test.h b/dex2oat/linker/image_test.h
index 7209fbf..a0f1093 100644
--- a/dex2oat/linker/image_test.h
+++ b/dex2oat/linker/image_test.h
@@ -75,7 +75,7 @@
 
 class ImageTest : public CommonCompilerDriverTest {
  protected:
-  virtual void SetUp() {
+  void SetUp() override {
     ReserveImageSpace();
     CommonCompilerTest::SetUp();
   }