[turbofan] Add initial support for global specialization.

test/cctest/test-compiler.cc

Index: test/cctest/test-compiler.cc
diff --git a/test/cctest/test-compiler.cc b/test/cctest/test-compiler.cc
index 6f8af3b3dd5cef94330480c5807be8e34ef4d8fd..da8f8fc89a0c9be0c4ba1ea176f985dee399b316 100644
--- a/test/cctest/test-compiler.cc
+++ b/test/cctest/test-compiler.cc
@@ -400,6 +400,7 @@ TEST(OptimizedCodeSharing2) {
   if (FLAG_stress_compaction) return;
   FLAG_allow_natives_syntax = true;
   FLAG_cache_optimized_code = true;
+  FLAG_native_context_specialization = false;
   FLAG_turbo_cache_shared_code = true;
   const char* flag = "--turbo-filter=*";
   FlagList::SetFlagsFromString(flag, StrLength(flag));
@@ -455,6 +456,7 @@ TEST(OptimizedCodeSharing3) {
   if (FLAG_stress_compaction) return;
   FLAG_allow_natives_syntax = true;
   FLAG_cache_optimized_code = true;
+  FLAG_native_context_specialization = false;
   FLAG_turbo_cache_shared_code = true;
   const char* flag = "--turbo-filter=*";
   FlagList::SetFlagsFromString(flag, StrLength(flag));