[turbofan] Make new.target explicit in JSCallDescriptor.

src/mips/macro-assembler-mips.h

Index: src/mips/macro-assembler-mips.h
diff --git a/src/mips/macro-assembler-mips.h b/src/mips/macro-assembler-mips.h
index 8890be8131cf5eb9678ca9fe14945020952ce2a8..f9c1d3c611bbc602c2a0c10dc44638245d520a2c 100644
--- a/src/mips/macro-assembler-mips.h
+++ b/src/mips/macro-assembler-mips.h
@@ -23,6 +23,7 @@ const Register kInterpreterBytecodeOffsetRegister = {Register::kCode_t4};
 const Register kInterpreterBytecodeArrayRegister = {Register::kCode_t5};
 const Register kInterpreterDispatchTableRegister = {Register::kCode_t6};
 const Register kJavaScriptCallArgCountRegister = {Register::kCode_a0};
+const Register kJavaScriptCallNewTargetRegister = {Register::kCode_a3};
 const Register kRuntimeCallFunctionRegister = {Register::kCode_a1};
 const Register kRuntimeCallArgCountRegister = {Register::kCode_a0};