This change created a CFv2 build target and provided two
implementations of the FuchsiaEmulator, so that I can continually work
on both CFv2 build and test script integration independently.
The v2 target can be built with
```
tools/build.py --os fuchsia --mode release fuchsia_ffi_test_package_cfv2
```
And v2 FuchsiaEmulator implementation can be triggered with
FUCHSIA_CFV2 environment variable.
Bug: #38752
Change-Id: I31936a2ca967fbfeb2bc5628e2f005aef6762687
Reviewed-on: https://dart-review.googlesource.com/c/sdk/+/322583
Reviewed-by: Alexander Thomas <athom@google.com>
Reviewed-by: Ryan Macnak <rmacnak@google.com>
Commit-Queue: Zijie He <zijiehe@google.com>
Zijie He
5282f6e33f