ART: Move DexFileStringEquals to DexFile

Avoid a static function in an inline header being shared.

Bug: 119869270
Test: mmma art
Change-Id: If10189f92bca71c8bd3ef679bdc48a0dbc113fa3
diff --git a/runtime/art_method.cc b/runtime/art_method.cc
index dd5b0d5..dd62853 100644
--- a/runtime/art_method.cc
+++ b/runtime/art_method.cc
@@ -189,7 +189,7 @@
   }
   const DexFile* dex_file2 = other->GetDexFile();
   const dex::MethodId& mid2 = dex_file2->GetMethodId(other->GetDexMethodIndex());
-  if (!DexFileStringEquals(dex_file, mid.name_idx_, dex_file2, mid2.name_idx_)) {
+  if (!DexFile::StringEquals(dex_file, mid.name_idx_, dex_file2, mid2.name_idx_)) {
     return false;  // Name mismatch.
   }
   return dex_file->GetMethodSignature(mid) == dex_file2->GetMethodSignature(mid2);