re PR go/80128 (go1: internal compiler error: in write_specific_type_functions, at go/gofrontend/types.cc:2002)

	PR go/80128
    compiler: check backend alignment for memequalNN functions
    
    The code was assuming the usual required alignment for the memequalNN
    functions (16 bits for int16, 32 for int32, etc.). However, on m68k
    the required alignment of int32 is only 16 bits. Assuming the
    memequalNN alignment caused the compiler to incorrectly decide that
    int32 required a specially generated function rather than calling
    memequal32. This then crashed if the type descriptor were generated
    after type-specific functions had been written.
    
    Fixes GCC PR 80128.
    
    Reviewed-on: https://go-review.googlesource.com/38433

From-SVN: r246382