[XI]WatchOS apps fail to build with error "Undefined symbols for architecture armv7k" using XI with mono-2017-12 support

[GouriKumari]

Steps to Reproduce

1. Open or create a new watchOS sample
2. Build it with Release|iPhone config

Expected Behavior

App should build successfully

Actual Behavior

App fails to build with error: https://gist.github.com/GouriKumari/66f9a07284774f479ebea69877922ac6 .
This issue occurs only with Release|iPhone config.

Environment

Test Env: https://gist.github.com/GouriKumari/af3f4d4338773d389c4091230574f4f8

Build Logs

Sample: http://xqa.blob.core.windows.net/gist/report-929e3b199cb1436cafe0172abb4f6e76.txt
Sample: http://xqa.blob.core.windows.net/gist/report-54386a93871c4158bd7954bd60c731c9.txt
Template: https://gist.github.com/GouriKumari/f85e3aaf7d56e32b9d4701a341576700

Example Project: https://github.com/olegoid/SubmissionSamples/tree/master/WatchOS

[mandel-macaque]

This issue was moved to mono/mono#6948

[mandel-macaque]

Moving to mono as per comment here: #3421 (comment)