ART: Fix tidy warnings

Switch to char versions of find variants.

Add "explicit" constructor variants or refactor and
remove defaults.

Use const references.

Bug: 32619234
Test: m test-art-host
Change-Id: I970cc2f47d6cf8f0c74104b994b075b2fafb3d45
diff --git a/runtime/dex_file_verifier_test.cc b/runtime/dex_file_verifier_test.cc
index e392870..3801c22 100644
--- a/runtime/dex_file_verifier_test.cc
+++ b/runtime/dex_file_verifier_test.cc
@@ -58,7 +58,7 @@
 
   void VerifyModification(const char* dex_file_base64_content,
                           const char* location,
-                          std::function<void(DexFile*)> f,
+                          const std::function<void(DexFile*)>& f,
                           const char* expected_error) {
     size_t length;
     std::unique_ptr<uint8_t[]> dex_bytes(DecodeBase64(dex_file_base64_content, &length));