zlib: fix assert fail for bad write in object mode

add4b0ab introduced a regression from Node 8 to Node 9 by removing the ArrayBuffer.isView(chunk) check in Zlib.prototype._transform without properly forcing opts.objectMode to false in the constructor because the change to opts occurs after opts has been passed to the Transform constructor. This commit fixes the issue by moving the call to Transform after the changes to opts.

The regression can be demonstrated by running

node -e 'require("zlib").Gunzip({objectMode: true}).write({})'

On Node 8 this correctly throws a TypeError:

events.js:183
      throw er; // Unhandled 'error' event
      ^

TypeError: invalid input
    at Gunzip._transform (zlib.js:367:15)
    at Gunzip.Transform._read (_stream_transform.js:186:10)
    at Gunzip.Transform._write (_stream_transform.js:174:12)
    at doWrite (_stream_writable.js:387:12)
    at writeOrBuffer (_stream_writable.js:373:5)
    at Gunzip.Writable.write (_stream_writable.js:290:11)
    at [eval]:1:44
    at ContextifyScript.Script.runInThisContext (vm.js:50:33)
    at Object.runInThisContext (vm.js:139:38)
    at Object.<anonymous> ([eval]-wrapper:6:22)

On Node 9 this causes a crash due to an assertion failure:

node[21732]: ../src/node_zlib.cc:179:static void node::{anonymous}::ZCtx::Write(const v8::FunctionCallbackInfo<v8::Value>&) [with bool async = true]: Assertion `Buffer::HasInstance(args[1])' failed.
 1: node::Abort() [node]
 2: node::Assert(char const* const (*) [4]) [node]
 3: 0x1250916 [node]
 4: v8::internal::FunctionCallbackArguments::Call(void (*)(v8::FunctionCallbackInfo<v8::Value> const&)) [node]
 5: 0xb7547c [node]
 6: v8::internal::Builtin_HandleApiCall(int, v8::internal::Object**, v8::internal::Isolate*) [node]
 7: 0x20c44b8842fd
Aborted

Checklist

• make -j4 test (UNIX), or vcbuild test (Windows) passes
• tests and/or benchmarks are included
• commit message follows commit guidelines

Affected core subsystem(s)

zlib