ci: build and test Rust on all platforms

I believe we didn't currently due this due to cross-compiling issues.
Now that we've adopted native ARM runners everywhere we can have nice
things.

Author: indygreg

.github/workflows/test.yml

@@ -77,7 +77,6 @@ jobs:
           architecture: ${{ matrix.arch }}
 
       - name: Install Rust
-        if: matrix.arch == 'x64'
         uses: dtolnay/rust-toolchain@v1
         with:
           toolchain: stable
@@ -90,17 +89,11 @@ jobs:
           python -m pip install --require-hashes -r ci/requirements.txt
 
       - name: Build (Rust)
-        if: matrix.arch == 'x64'
         env:
           PIP_CONSTRAINT: 'ci/constraints.txt'
         run: |
           python -m pip install --config-settings='--build-option=--rust-backend' -e .
 
-      - name: Build (No Rust)
-        if: matrix.arch != 'x64'
-        run: |
-          python -m pip install -e .
-
       - name: Test C Backend
         run: |
           pytest --numprocesses=auto --hypothesis-profile=${HYPOTHESIS_PROFILE} -v tests/
@@ -112,7 +105,6 @@ jobs:
           pytest --numprocesses=auto --hypothesis-profile=${HYPOTHESIS_PROFILE} -v tests/
 
       - name: Test Rust Backend
-        if: matrix.arch == 'x64'
         # Rust backend is currently experimental. So ignore failures in it.
         continue-on-error: true
         env: