PR go/78144
    libgo: incorporate fix for timezone test
    
    This brings over the test-only fix for issue 17276 into gccgo/libgo
    (with tzdata-2016g there is a new zone abbreviation).  This is a
    copy of https://golang.org/cl/29995.
    
    Reviewed-on: https://go-review.googlesource.com/32182

From-SVN: r241661