cmd/gobind: make sure to set exit code on type checking errors
cmd/gobind: make sure to set exit code on type checking errors

Change-Id: Iea30db321c53b37b41a2b18689c5f724938a1593
Reviewed-on: https://go-review.googlesource.com/108135
Reviewed-by: Hyang-Ah Hana Kim <d7e82c3c07f92613bcbf9a1e88f6b96c13caa3b0@gmail.com>

golang/mobile,golang/mobile,golang/mobile,golang/mobile