Disable "__builtin_func" when converting mk to bp

The "__builtin_func" doesn't work in soong. The converting tool
androidmk should disable this feature.

Bug: 329770862
Test: 1. cd build/soong/androidmk/androidmk
      2. go test -run TestEndToEnd
Change-Id: I1de04e4e1a34fb7335e0013f59b33f7f2673722a