MIPS: Fix NaN handling for start index in ArraySplice.

src/builtins.cc

Index: src/builtins.cc
diff --git a/src/builtins.cc b/src/builtins.cc
index 30edf579e62234fdd162af7a8ea99c6fb580f0ee..b10495eb3b2d3c0e40adcf5a94148c9dfb0f41eb 100644
--- a/src/builtins.cc
+++ b/src/builtins.cc
@@ -934,7 +934,7 @@ BUILTIN(ArraySplice) {
       if (start < kMinInt || start > kMaxInt) {
         return CallJsBuiltin(isolate, "ArraySplice", args);
       }
-      relative_start = static_cast<int>(start);
+      relative_start = std::isnan(start) ? 0 : static_cast<int>(start);
     } else if (!arg1->IsUndefined()) {
       return CallJsBuiltin(isolate, "ArraySplice", args);
     }