add EMULATED define to CPPFLAGS for emulated targets

[adamdebek]

JIRA: CI-501

Description

Motivation and Context

Types of changes

• Bug fix (non-breaking change which fixes an issue)
• New feature (non-breaking change which adds functionality)
• Breaking change (fix or feature that would cause existing functionality to change)
• Chore (refactoring, style fixes, git/CI config, submodule management, no code logic changes)

How Has This Been Tested?

• Already covered by automatic testing.
• New test added: (add PR link here).
• Tested by hand on: (list targets here).

Checklist:

• My change requires a change to the documentation.
• I have updated the documentation accordingly.
• I have added tests to cover my changes.
• All new and existing linter checks and tests passed.
• My changes generate no new compilation warnings for any of the targets.

Special treatment

• This PR needs additional PRs to work (list the PRs, preferably in merge-order).
• I will merge this PR by myself when appropriate.

[github-actions]

Unit Test Results

7 725 tests  +2   7 010 ✅ +2   36m 57s ⏱️ -16s
  445 suites +2     715 💤 ±0 
    1 files   ±0       0 ❌ ±0 

Results for commit b95d4ed. ± Comparison against base commit 4183f39.

[anglov]

I have no knowledge about reason why you want to add it. Maybe @nalajcie can help?

Anyways If you ask me, I don't like assuming about emulated or not target basing on TARGET_PROJECT. In current project we have emulated target riscv64-generic-spike

If you really need that variable, I would tihnk about passing it explicitly from _project files.

[adamdebek]

After nalajcie comment here: phoenix-rtos/phoenix-rtos-tests#378, tihs pr is no longer relevant.