re PR go/67101 (mprof.goc:408:5: error: calling ‘__builtin_frame_address’ with a nonzero argument is unsafe [-Werror=frame-address])

	PR go/67101

    runtime: Remove call to __builtin_frame_address.
    
    __builtin_frame_address was only supposed to use nonzero arguments
    for debugging purposes.  Calling it with nonzero arguments can have
    unpredictable results and uses are now marked unsafe when
    -Wframe-address is enabled.
    
    Reviewed-on: https://go-review.googlesource.com/13063

From-SVN: r226525