Cleanup String.<init> handling.

Move everything to one place (currently well_known_classes.cc, but
no strong preference) and define a macro to easily handle the list
of affected methods.

test: m test-art-host
test: m test-art-target
Change-Id: Ib8372d130d5458516a1f1ae31014afc76037fc34
diff --git a/compiler/optimizing/code_generator_arm.cc b/compiler/optimizing/code_generator_arm.cc
index 6be458c..55e1221 100644
--- a/compiler/optimizing/code_generator_arm.cc
+++ b/compiler/optimizing/code_generator_arm.cc
@@ -6748,10 +6748,13 @@
 
   Location callee_method = temp;  // For all kinds except kRecursive, callee will be in temp.
   switch (invoke->GetMethodLoadKind()) {
-    case HInvokeStaticOrDirect::MethodLoadKind::kStringInit:
+    case HInvokeStaticOrDirect::MethodLoadKind::kStringInit: {
+      uint32_t offset =
+          GetThreadOffset<kArmPointerSize>(invoke->GetStringInitEntryPoint()).Int32Value();
       // temp = thread->string_init_entrypoint
-      __ LoadFromOffset(kLoadWord, temp.AsRegister<Register>(), TR, invoke->GetStringInitOffset());
+      __ LoadFromOffset(kLoadWord, temp.AsRegister<Register>(), TR, offset);
       break;
+    }
     case HInvokeStaticOrDirect::MethodLoadKind::kRecursive:
       callee_method = invoke->GetLocations()->InAt(invoke->GetSpecialInputIndex());
       break;