Fix bin-packing behavior of constructor initialziers.

In Google style, constructor initializers need to be all on one line or
one initializer per line if that does not fit. Without this patch, this
non-bin-packing-behavior incorrectly extends to the parameters of the
initializers.

Before:
Constructor()
    : aaaaa(aaaaaaaaaaaaaaaaaaaaaa,
            aaaaaaaaaaaaaaaaaaaaaa,
            aaaaaaaaaaaaaaaaaaaaaa) {}

After:
Constructor()
    : aaaaa(aaaaaaaaaaaaaaaaaaaaaa, aaaaaaaaaaaaaaaaaaaaaa,
            aaaaaaaaaaaaaaaaaaaaaa) {}