8277385: Zero: Enable CompactStrings support

Backport-of: 3f847fe89a088d6921107ca887a7a1bace871bd6

Author: shipilev

src/hotspot/cpu/zero/globals_zero.hpp

@@ -77,8 +77,7 @@ define_pd_global(uintx, TypeProfileLevel, 0);
 
 define_pd_global(bool, PreserveFramePointer, false);
 
-// No performance work done here yet.
-define_pd_global(bool, CompactStrings, false);
+define_pd_global(bool, CompactStrings, true);
 
 define_pd_global(bool, ThreadLocalHandshakes, false);