Reland "Make compiler/optimizing/ symbols hidden."
This reverts commit 0a51605ddd81635135463dab08b6f7c21b58ffb0.
Reason for revert: Reland after some of the required work
was merged in other CLs.
Also address a TODO from the original CL to mark required
symbols with EXPORT in `intrinsic_objects.h`.
Also mark symbols in new files as HIDDEN.
Bug: 186902856
Test: m test-art-host-gtest
Test: testrunner.py --host --optimizing
Change-Id: I936d448983928af23614ca82c2d0bf9a645e2c52
diff --git a/compiler/optimizing/instruction_simplifier_x86.cc b/compiler/optimizing/instruction_simplifier_x86.cc
index 2d8f94a..805dd49 100644
--- a/compiler/optimizing/instruction_simplifier_x86.cc
+++ b/compiler/optimizing/instruction_simplifier_x86.cc
@@ -17,7 +17,7 @@
#include "instruction_simplifier_x86_shared.h"
#include "code_generator_x86.h"
-namespace art {
+namespace art HIDDEN {
namespace x86 {