Auto merge of #29963 - mrobinson:run-unit-tests-when-using-try-platform, r=atbrakhi

When using "try-<platform>" trigger unit tests

There is currently no way to trigger unit tests using the bors-servo try
infrastructure. This change makes it so that using try-<platform>
triggers unit tests for that platform. This will be especially useful
when testing changes for Windows before trying to land them.

<!-- Please describe your changes on the following line: -->

---
<!-- Thank you for contributing to Servo! Please replace each `[ ]` by `[X]` when the step is complete, and replace `___` with appropriate data: -->
- [x] `./mach build -d` does not report any errors
- [x] `./mach test-tidy` does not report any errors
- [x] These changes do not require tests because they are just GitHub Actions changes.

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.github/workflows/linux.yml

@@ -78,7 +78,7 @@ jobs:
       - name: Script tests
         run: ./mach test-scripts
       - name: Unit tests
-        if: ${{ inputs.unit-tests }}
+        if: ${{ inputs.unit-tests || github.ref_name == 'try-linux' }}
         run: python3 ./mach test-unit --release --with-${{ env.LAYOUT }}
       - name: Rename build timing
         run: cp -r target/cargo-timings target/cargo-timings-linux-${{ env.LAYOUT }}

.github/workflows/mac.yml

@@ -66,7 +66,7 @@ jobs:
       - name: Script tests
         run: ./mach test-scripts
       - name: Unit tests
-        if: ${{ inputs.unit-tests }}
+        if: ${{ inputs.unit-tests || github.ref_name == 'try-mac' }}
         run: python3 ./mach test-unit --release --with-${{ env.LAYOUT }}
       - name: Package
         run: python3 ./mach package --release

.github/workflows/windows.yml

@@ -70,7 +70,7 @@ jobs:
       - name: Smoketest
         run: python mach smoketest --angle
       - name: Unit tests
-        if: ${{ inputs.unit-tests }}
+        if: ${{ inputs.unit-tests || github.ref_name == 'try-windows' }}
         run: python mach test-unit --release --with-${{ env.LAYOUT }}
       - name: Rename build timing
         run: cp C:\a\servo\servo\target\cargo-timings C:\a\servo\servo\target\cargo-timings-windows-${{ env.LAYOUT }} -Recurse