Make the strict-mode calling convention for contextual calls the default one.

src/v8globals.h

Index: src/v8globals.h
diff --git a/src/v8globals.h b/src/v8globals.h
index da290b243fe6474a1ab6670c2520048749e0c5de..a85c828c7ca2d6255669c946cfc51fb45a78eb9e 100644
--- a/src/v8globals.h
+++ b/src/v8globals.h
@@ -289,14 +289,9 @@ enum CheckType {
 
 
 enum CallFunctionFlags {
-  NO_CALL_FUNCTION_FLAGS = 0,
-  // Receiver might implicitly be the global objects. If it is, the
-  // hole is passed to the call function stub.
-  RECEIVER_MIGHT_BE_IMPLICIT = 1 << 0,
-  // Receiver is implicit and the hole has been passed to the stub.
-  RECEIVER_IS_IMPLICIT = 1 << 1,
+  NO_CALL_FUNCTION_FLAGS,
   // The call target is cached in the instruction stream.
-  RECORD_CALL_TARGET = 1 << 2
+  RECORD_CALL_TARGET
 };