Control flow analysis for inline assembly.

test/libsolidity/syntaxTests/controlFlow/unreachableCode/assembly/for_continue.sol

@@ -0,0 +1,12 @@
+contract C {
+    function f() public pure {
+        assembly {
+            for { let a := 0} lt(a,1) { a := add(a, 1) } {
+                continue
+                let b := 42
+            }
+        }
+    }
+}
+// ----
+// Warning: (163-174): Unreachable code.