scaletempo: S16 uses S32 temporary buffers, float/double their own type
scaletempo: S16 uses S32 temporary buffers, float/double their own type

Make sure to allocate not only a S16 buffer for S16 but a twice as big one to
hold S32.

https://bugzilla.gnome.org/show_bug.cgi?id=765116

hizukiayaka/gst-plugins-good,StreamUtils/gst-plugins-good,GStreamer/gst-plugins-good,pexip/gst-plugins-good,hizukiayaka/gst-plugins-good,hizukiayaka/gst-plugins-good,GStreamer/gst-plugins-good,GStreamer/gst-plugins-good,stfl/gst-plugins-good,hizukiayaka/gst-plugins-good,GrokImageCompression/gst-plugins-good,stfl/gst-plugins-good,StreamUtils/gst-plugins-good,pexip/gst-plugins-good,StreamUtils/gst-plugins-good,GrokImageCompression/gst-plugins-good,stfl/gst-plugins-good,stfl/gst-plugins-good,GrokImageCompression/gst-plugins-good,GStreamer/gst-plugins-good,StreamUtils/gst-plugins-good,GrokImageCompression/gst-plugins-good,pexip/gst-plugins-good,pexip/gst-plugins-good,pexip/gst-plugins-good