Take revert statement into account in control flow graph.

test/libsolidity/syntaxTests/errors/duplicate.sol

@@ -0,0 +1,21 @@
+==== Source: A ====
+
+error E();
+
+==== Source: B ====
+
+error E();
+
+==== Source: C ====
+
+import "A" as A;
+import "B" as B;
+
+contract Test {
+    function f() public pure {
+        revert A.E();
+    }
+    function g() public pure {
+        revert B.E();
+    }
+}

test/libsolidity/syntaxTests/errors/unreachable.sol

@@ -0,0 +1,10 @@
+contract C {
+    error E();
+    uint x = 2;
+    function f() public {
+        revert E();
+        x = 4;
+    }
+}
+// ----
+// Warning 5740: (98-103): Unreachable code.