Update core-lib and add IfNil to benchmark setup (#19)

Author: smarr

.github/workflows/ci.yml

@@ -7,10 +7,10 @@ jobs:
     runs-on: ubuntu-latest
 
     steps:
-      - uses: actions/checkout@v3
+      - uses: actions/checkout@v4
 
       - name: Use Node.js
-        uses: actions/setup-node@v3
+        uses: actions/setup-node@v4
 
       - run: ./som.sh -cp core-lib/Smalltalk core-lib/TestSuite/TestHarness.som
       - run: ./som.sh -cp core-lib/Smalltalk:core-lib/TestSuite:core-lib/SomSom/src/compiler:core-lib/SomSom/src/vm:core-lib/SomSom/src/vmobjects:core-lib/SomSom/src/interpreter:core-lib/SomSom/src/primitives core-lib/SomSom/tests/SomSomTests.som

core-lib

@@ -53,6 +53,7 @@ benchmark_suites:
             - FieldLoop:    {extra_args: 1}
             - WhileLoop:    {extra_args: 10}
             - Mandelbrot:   {extra_args: 30}
+            - IfNil:        {extra_args: 10}
 
     interpreter:
         description: Basic interpreter benchmarks for comparing performance of most basic concepts.