[builtins] Provide Math.floor as TurboFan builtin.

src/bootstrapper.cc

Index: src/bootstrapper.cc
diff --git a/src/bootstrapper.cc b/src/bootstrapper.cc
index db4a157623df5214b7ea5028cbef0981a7bc517d..6119c05649f8a7771063e65c53a5ee133d4cf6be 100644
--- a/src/bootstrapper.cc
+++ b/src/bootstrapper.cc
@@ -1519,6 +1519,9 @@ void Genesis::InitializeGlobal(Handle<JSGlobalObject> global_object,
     SimpleInstallFunction(math, "acos", Builtins::kMathAcos, 1, true);
     SimpleInstallFunction(math, "asin", Builtins::kMathAsin, 1, true);
     SimpleInstallFunction(math, "atan", Builtins::kMathAtan, 1, true);
+    Handle<JSFunction> math_floor =
+        SimpleInstallFunction(math, "floor", Builtins::kMathFloor, 1, true);
+    native_context()->set_math_floor(*math_floor);
     SimpleInstallFunction(math, "fround", Builtins::kMathFround, 1, true);
     SimpleInstallFunction(math, "imul", Builtins::kMathImul, 2, true);
     SimpleInstallFunction(math, "max", Builtins::kMathMax, 2, false);