Add a little headroom to the stack when converting an exception JS -> C++

Summary:
This was causing an exception cascade leading to production
errors.  Added a test which repros the problem and passes with the
fix.

Changelog: [Internal]

Reviewed By: tmikov

Differential Revision: D20408858

fbshipit-source-id: 3fa9b8669bf3bf7617bfc05ef8f23d52bc969b4e

ReactCommon/jsi/jsi/test/testlib.cpp

@@ -1029,6 +1029,30 @@ TEST_P(JSITest, JSErrorDoesNotInfinitelyRecurse) {
   rt.global().setProperty(rt, "Error", globalError);
 }
 
+TEST_P(JSITest, JSErrorStackOverflowHandling) {
+  rt.global().setProperty(
+      rt,
+      "callSomething",
+      Function::createFromHostFunction(
+          rt,
+          PropNameID::forAscii(rt, "callSomething"),
+          0,
+          [this](
+              Runtime& rt2,
+              const Value& thisVal,
+              const Value* args,
+              size_t count) {
+            EXPECT_EQ(&rt, &rt2);
+            return function("function() { return 0; }").call(rt);
+          }));
+  try {
+    eval("(function f() { callSomething(); f.apply(); })()");
+    FAIL();
+  } catch (const JSError& ex) {
+    EXPECT_NE(std::string(ex.what()).find("exceeded"), std::string::npos);
+  }
+}
+
 TEST_P(JSITest, ScopeDoesNotCrashTest) {
   Scope scope(rt);
   Object o(rt);