Make enabling of CSA verifier a build-time flag

gypfiles/features.gypi

Index: gypfiles/features.gypi
diff --git a/gypfiles/features.gypi b/gypfiles/features.gypi
index f82a59f0f82f53718bae76fc53e248c89f541577..6cce64ca2090ed6cab4bd2ce77686e179374528e 100644
--- a/gypfiles/features.gypi
+++ b/gypfiles/features.gypi
@@ -33,6 +33,8 @@
 
     'v8_enable_gdbjit%': 0,
 
+    'v8_enable_verify_csa%': 0,
+
     'v8_object_print%': 0,
 
     'v8_enable_verify_heap%': 0,
@@ -78,6 +80,9 @@
       ['v8_enable_gdbjit==1', {
         'defines': ['ENABLE_GDB_JIT_INTERFACE',],
       }],
+      ['v8_enable_verify_csa==1', {
+        'defines': ['ENABLE_VERIFY_CSA',],
+      }],
       ['v8_object_print==1', {
         'defines': ['OBJECT_PRINT',],
       }],