chore: remove dependency on in-source compilation of bin/ directory (…

…#32476)

The `bin/cdk` binary relies on the fact that `bin/cdk.ts` undergoes an in-source compilation, producing `bin/cdk.js` which is then required.

This fails in a different setup where we only compile the `lib/` directory and nothing else.

So skip one level of indirection: just put the code that loads the actual CLI entry point directly in the bash wrapper.

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packages/aws-cdk/bin/cdk

@@ -1,6 +1,6 @@
 #!/usr/bin/env node
-
 // source maps must be enabled before importing files
 process.setSourceMapsEnabled(true);
+const { cli } = require("../lib/cli");
 
-require('./cdk.js');
+cli();