[housekeeping] Remove unused test fixtures

We don't use these fixtures, let's just clean them up.

compiler/packages/babel-plugin-react-forget/src/__tests__/fixtures/todo/README.md

@@ -1,5 +0,0 @@
-## TODOs
-
-This directory contains files that are currently crashing the compiler and
-should be moved to `../transform/` as a potential new fixture once the crash
-is fixed.

compiler/packages/babel-plugin-react-forget/src/__tests__/fixtures/todo/cfg-for-of-statement-with-assignment.js

@@ -1,15 +0,0 @@
-// @Out DumpCFG
-function useForOfStatement(x) {
-  "use forget";
-  const items = [];
-  let item;
-  for (item of x) {
-    if (shouldBreak()) {
-      break;
-    } else if (shouldContinue()) {
-      continue;
-    }
-    items.push(item);
-  }
-  return items;
-}