chakrashim: correct function callback context

A native function callback is expected to be invoked in its creation
context. Enter the callee context before invoking native callback.

Fixes several 'repl` related tests:
- parallel/test-repl-require
- parallel/test-repl-syntax-error-stack
- addons/repl-domain-abort/test

PR-URL: #54
Reviewed-By: Sandeep Agarwal <Agarwal.Sandeep@microsoft.com>

Author: Jianchun Xu

deps/chakrashim/src/v8functiontemplate.cc

@@ -86,6 +86,10 @@ struct FunctionCallbackData {
                                              JsValueRef *arguments,
                                              unsigned short argumentCount,
                                              void *callbackState) {
+    // Script engine could have switched context. Make sure to invoke the
+    // callback in the current callee context.
+    ContextShim* contextShim = IsolateShim::GetContextShimOfObject(callee);
+    ContextShim::Scope contextScope(contextShim);
     HandleScope scope(nullptr);
 
     JsValueRef functionCallbackDataRef = JsValueRef(callbackState);