Add circom test w/ circuit for CircomVerifierProof

Add circom test with circuit for CircomVerifierProofs, which allows to
automatically check that the data generated from arbo matches the circom
circuit of a SMTVerifierProof.
Added also GHA workflow to test the circuits with the output of arbo
code.

.github/workflows/circomtest.yml

@@ -0,0 +1,24 @@
+name: CircomTest
+on: [ push, pull_request ]
+jobs:
+  test:
+    runs-on: ubuntu-latest
+    strategy:
+      matrix:
+        node-version: [14.x]
+        go-version: [1.16.x]
+    steps:
+    - uses: actions/checkout@v2
+    - name: Use Node.js ${{ matrix.node-version }}
+      uses: actions/setup-node@v1
+      with:
+        node-version: ${{ matrix.node-version }}
+    - name: Install Go
+      uses: actions/setup-go@v1
+      with:
+        go-version: ${{ matrix.go-version }}
+    - name: run circom tests
+      run: |
+        cd testvectors/circom
+        npm install
+        npm run test