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/tools/cpp-define-generator/main.cc b/tools/cpp-define-generator/main.cc
index a1b463a..fc99f8a 100644
--- a/tools/cpp-define-generator/main.cc
+++ b/tools/cpp-define-generator/main.cc
@@ -59,12 +59,12 @@
 }
 
 template <typename T>
-void cpp_define(std::string name, T value) {
+void cpp_define(const std::string& name, T value) {
   std::cout << "#define " << name << " " << pretty_format(value) << std::endl;
 }
 
 template <typename T>
-void emit_check_eq(T value, std::string expr) {
+void emit_check_eq(T value, const std::string& expr) {
   std::cout << "DEFINE_CHECK_EQ(" << value << ", (" << expr << "))" << std::endl;
 }