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/native/dalvik_system_VMDebug.cc b/runtime/native/dalvik_system_VMDebug.cc
index 8d85425..adf35b6 100644
--- a/runtime/native/dalvik_system_VMDebug.cc
+++ b/runtime/native/dalvik_system_VMDebug.cc
@@ -420,8 +420,10 @@
   }
 }
 
-static bool SetRuntimeStatValue(JNIEnv* env, jobjectArray result, VMDebugRuntimeStatId id,
-                                std::string value) {
+static bool SetRuntimeStatValue(JNIEnv* env,
+                                jobjectArray result,
+                                VMDebugRuntimeStatId id,
+                                const std::string& value) {
   ScopedLocalRef<jstring> jvalue(env, env->NewStringUTF(value.c_str()));
   if (jvalue.get() == nullptr) {
     return false;