[generators] Implement %GeneratorGetSourcePosition.

src/compiler/js-operator.cc

Index: src/compiler/js-operator.cc
diff --git a/src/compiler/js-operator.cc b/src/compiler/js-operator.cc
index 4cbf21d83b422872dc215a04f76f7b0cab4978b6..89c0eee0b49a980e15fe64f5ae894e54bca93643 100644
--- a/src/compiler/js-operator.cc
+++ b/src/compiler/js-operator.cc
@@ -722,7 +722,7 @@ const Operator* JSOperatorBuilder::GeneratorStore(int register_count) {
   return new (zone()) Operator1<int>(                   // --
       IrOpcode::kJSGeneratorStore, Operator::kNoThrow,  // opcode
       "JSGeneratorStore",                               // name
-      2 + register_count, 1, 1, 0, 1, 0,                // counts
+      3 + register_count, 1, 1, 0, 1, 0,                // counts
       register_count);                                  // parameter
 }