compiler/natives/src/reflect: Update signatures.
compiler/natives/src/reflect: Update signatures.

chanrecv, chansend no longer accept t *rtype first parameter. Conveniently,
it was unused anyway.

makemap now accepts an additional cap int paraameter. A TODO comment is
added to make use of it, if needed/possible.

structField's offset field was renamed/combined with anonymous bit to
become offsetAnon. The least significant bit is the anonymous bit,
and byte offset of field is stored shifted left by 1 bit.

gopherjs/gopherjs,gopherjs/gopherjs,gopherjs/gopherjs,gopherjs/gopherjs,gopherjs/gopherjs