Moving some tests to semantic tests.

test/libsolidity/semanticTests/functionCall/calling_other_functions.sol

@@ -0,0 +1,22 @@
+contract collatz {
+    function run(uint x) public returns(uint y) {
+        while ((y = x) > 1) {
+            if (x % 2 == 0) x = evenStep(x);
+            else x = oddStep(x);
+        }
+    }
+    function evenStep(uint x) public returns(uint y) {
+        return x / 2;
+    }
+    function oddStep(uint x) public returns(uint y) {
+        return 3 * x + 1;
+    }
+}
+// ====
+// compileViaYul: also
+// ----
+// run(uint256): 0 -> 0
+// run(uint256): 1 -> 1
+// run(uint256): 2 -> 1
+// run(uint256): 8 -> 1
+// run(uint256): 127 -> 1