tools: update V8 gypfiles for 12.1

Refs: v8/v8@08c87ab
Refs: v8/v8@d136cd9

Author: targos

tools/v8_gypfiles/features.gypi

@@ -260,6 +260,9 @@
     # Allow for JS promise hooks (instead of just C++).
     'v8_enable_javascript_promise_hooks%': 0,
 
+    # Allow for JS promise hooks (instead of just C++).
+    'v8_enable_continuation_preserved_embedder_data%': 1,
+
     # Enable allocation folding globally (sets -dV8_ALLOCATION_FOLDING).
     # When it's disabled, the --turbo-allocation-folding runtime flag will be ignored.
     'v8_enable_allocation_folding%': 1,
@@ -501,6 +504,9 @@
       ['v8_enable_javascript_promise_hooks==1', {
         'defines': ['V8_ENABLE_JAVASCRIPT_PROMISE_HOOKS',],
       }],
+      ['v8_enable_continuation_preserved_embedder_data==1', {
+        'defines': ['V8_ENABLE_CONTINUATION_PRESERVED_EMBEDDER_DATA',],
+      }],
       ['v8_enable_allocation_folding==1', {
         'defines': ['V8_ALLOCATION_FOLDING',],
       }],

tools/v8_gypfiles/v8.gyp

@@ -389,6 +389,7 @@
           'variables': {
             'mksnapshot_flags': [
               '--turbo_instruction_scheduling',
+              '--stress-turbo-late-spilling',
               # In cross builds, the snapshot may be generated for both the host and
               # target toolchains.  The same host binary is used to generate both, so
               # mksnapshot needs to know which target OS to use at runtime.  It's weird,