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_mips.cc b/compiler/optimizing/code_generator_mips.cc
index 2b71da0..cf8928f 100644
--- a/compiler/optimizing/code_generator_mips.cc
+++ b/compiler/optimizing/code_generator_mips.cc
@@ -415,7 +415,7 @@
                                   this,
                                   IsDirectEntrypoint(kQuickInstanceofNonTrivial));
       CheckEntrypointTypes<
-          kQuickInstanceofNonTrivial, uint32_t, const mirror::Class*, const mirror::Class*>();
+          kQuickInstanceofNonTrivial, size_t, const mirror::Class*, const mirror::Class*>();
       Primitive::Type ret_type = instruction_->GetType();
       Location ret_loc = calling_convention.GetReturnLocation(ret_type);
       mips_codegen->MoveLocation(locations->Out(), ret_loc, ret_type);