8229967: Enable thread local handshakes on zero

Reviewed-by: sgehwolf, shade

src/hotspot/cpu/zero/globalDefinitions_zero.hpp

@@ -30,6 +30,8 @@
 #define SUPPORTS_NATIVE_CX8
 #endif
 
+#define THREAD_LOCAL_POLL
+
 #include <ffi.h>
 
 // Indicates whether the C calling conventions require that

src/hotspot/cpu/zero/globals_zero.hpp

@@ -76,7 +76,7 @@ define_pd_global(bool, PreserveFramePointer, false);
 // No performance work done here yet.
 define_pd_global(bool, CompactStrings, false);
 
-define_pd_global(bool, ThreadLocalHandshakes, false);
+define_pd_global(bool, ThreadLocalHandshakes, true);
 
 #define ARCH_FLAGS(develop, \
                    product, \