Binary encoding for empty funcref segment may use wrong flags?

[alexcrichton]

Given this *.wat:

(module
  (table 1 funcref)
  (elem (table 0) (i32.const 0) funcref))

this encodes as:

$ wat2wasm foo.wat --enable-all -o foo.wasm
$ wasm-objdump -x foo.wasm

foo.wasm:	file format wasm 0x1

Section Details:

Table[1]:
 - table[0] type=funcref initial=1
Elem[1]:
 - segment[0] flags=7 table=0 count=0
DataCount:
 - data count: 0

Here the element segment uses flags=7 but I think this one should more accurately use either 4 or 6 according to https://github.com/WebAssembly/bulk-memory-operations/blob/master/proposals/bulk-memory-operations/Overview.md#element-segments?

[binji]

Should be fixed in #1286