Prune empty case blocks before a default #4359

I think there's an opportunity to further optimize switch statements by removing empty case blocks before a default.

Input:

switch (globalThis.foo) {
  case 'first': {
    console.log('first');
  }
  case 'second':
  default: {
    console.log('default');
  }
}

Expected output:

switch (globalThis.foo) {
  case 'first': console.log('first');
  default: console.log('default');
}

Actual output (0.27.1):

switch (globalThis.foo) {
  case 'first': console.log('first');
  case 'second': // Unnecessary!
  default: console.log('default');
}

Playground link

I think you do need to keep case statements which contain expressions (case getSecond(): ...) as that's probably important for execution order and potential side effects. But I think any literal values should be safe to remove, and that's likely the most common case with switch statements.