Store snapshot templates in isolate, not context.

This lets us load the isolate without having to create a temp/dummy context
just to get the templates.

Call ContextDisposedNotification when a context is removed. Supposedly this can
help/hint to the isolate about memory management.

src/browser/js/Context.zig

@@ -166,8 +166,8 @@ pub fn deinit(self: *Context) void {
     }
 
     if (self.handle_scope) |*scope| {
-        scope.deinit();
         v8.v8__Context__Exit(self.handle);
+        scope.deinit();
     }
 }
 

src/browser/js/Env.zig

@@ -93,14 +93,10 @@ pub fn init(allocator: Allocator, platform: *const Platform, snapshot: *Snapshot
         var temp_scope: js.HandleScope = undefined;
         temp_scope.init(isolate);
         defer temp_scope.deinit();
-        const context_handle = isolate.createContextHandle(null, null);
-
-        v8.v8__Context__Enter(context_handle);
-        defer v8.v8__Context__Exit(context_handle);
 
         inline for (JsApis, 0..) |JsApi, i| {
             JsApi.Meta.class_id = i;
-            const data = v8.v8__Context__GetDataFromSnapshotOnce(context_handle, snapshot.data_start + i);
+            const data = v8.v8__Isolate__GetDataFromSnapshotOnce(isolate.handle, snapshot.data_start + i);
             const function_handle: *const v8.FunctionTemplate = @ptrCast(data);
             // Make function template global/persistent
             v8.v8__Global__New(isolate.handle, @ptrCast(function_handle), &globals[i]);

src/browser/js/ExecutionWorld.zig

@@ -158,6 +158,7 @@ pub fn removeContext(self: *ExecutionWorld) void {
     self.persisted_context.?.deinit();
     self.persisted_context = null;
 
+    self.env.isolate.notifyContextDisposed();
     _ = self.context_arena.reset(.{ .retain_with_limit = CONTEXT_ARENA_RETAIN });
 }
 

src/browser/js/Isolate.zig

@@ -57,6 +57,10 @@ pub fn lowMemoryNotification(self: Isolate) void {
     v8.v8__Isolate__LowMemoryNotification(self.handle);
 }
 
+pub fn notifyContextDisposed(self: Isolate) void {
+    _ = v8.v8__Isolate__ContextDisposedNotification(self.handle);
+}
+
 pub fn getHeapStatistics(self: Isolate) v8.HeapStatistics {
     var res: v8.HeapStatistics = undefined;
     v8.v8__Isolate__GetHeapStatistics(self.handle, &res);

src/browser/js/Snapshot.zig

@@ -179,7 +179,7 @@ pub fn create() !Snapshot {
         var last_data_index: usize = 0;
         inline for (JsApis, 0..) |_, i| {
             @setEvalBranchQuota(10_000);
-            const data_index = v8.v8__SnapshotCreator__AddData2(snapshot_creator, context, @ptrCast(templates[i]));
+            const data_index = v8.v8__SnapshotCreator__AddData(snapshot_creator, @ptrCast(templates[i]));
             if (i == 0) {
                 data_start = data_index;
                 last_data_index = data_index;