dex_cache: rewrite StringDexCachePair as DexCachePair<T>

.. with [T = mirror::String]. This is in preparation for introducing
a dex cache array for MethodTypes, which will be treated the same way.

Test: make test-art-host
bug: 30550796
Change-Id: Ief4455b4c6e4c9dd897f2c40b14b843a57b1dc8e
diff --git a/runtime/interpreter/interpreter_common.h b/runtime/interpreter/interpreter_common.h
index 814adf7..0feb013 100644
--- a/runtime/interpreter/interpreter_common.h
+++ b/runtime/interpreter/interpreter_common.h
@@ -254,9 +254,9 @@
   DCHECK_LT(string_idx % mirror::DexCache::kDexCacheStringCacheSize,
             declaring_class->GetDexFile().NumStringIds());
   mirror::String* string_ptr =
-      mirror::StringDexCachePair::LookupString(declaring_class->GetDexCacheStrings(),
-                                               string_idx,
-                                               mirror::DexCache::kDexCacheStringCacheSize).Read();
+      mirror::StringDexCachePair::Lookup(declaring_class->GetDexCacheStrings(),
+                                         string_idx,
+                                         mirror::DexCache::kDexCacheStringCacheSize).Read();
   if (UNLIKELY(string_ptr == nullptr)) {
     StackHandleScope<1> hs(self);
     Handle<mirror::DexCache> dex_cache(hs.NewHandle(declaring_class->GetDexCache()));