ART: Change return types of field access entrypoints

Ensure that return types guarantee full-width data as the compiled
code and mterp expect by using size_t and ssize_t.

This fixes Clang no longer sign-/zero-extending small return types.

Bug: 30232671
Test: m ART_TEST_RUN_TEST_NDEBUG=true ART_TEST_INTERPRETER=true test-art-host-run-test
Change-Id: Ic505befc6c94e2dccbc8abf2b13d4c2d662e68d1
diff --git a/compiler/optimizing/code_generator_x86_64.cc b/compiler/optimizing/code_generator_x86_64.cc
index a015893..bd4ded1 100644
--- a/compiler/optimizing/code_generator_x86_64.cc
+++ b/compiler/optimizing/code_generator_x86_64.cc
@@ -369,7 +369,7 @@
                                     dex_pc,
                                     this);
       CheckEntrypointTypes<
-          kQuickInstanceofNonTrivial, uint32_t, const mirror::Class*, const mirror::Class*>();
+          kQuickInstanceofNonTrivial, size_t, const mirror::Class*, const mirror::Class*>();
     } else {
       DCHECK(instruction_->IsCheckCast());
       x86_64_codegen->InvokeRuntime(QUICK_ENTRY_POINT(pCheckCast),