fix: dynamic require

[plainnany]

fix: issue27
demo: https://github.com/plainnany/vite-plugin-commonjs/tree/dynamic-demo/example

[yejimeiming]

Mybe the following code is better.

record.dynaimc = {
  importee: [],
- runtimeName: `__matchRequireRuntime${counter}__`,
+ runtimeName: `__matchRequireRuntime${counter++}__`,
  runtimeFn: '', // to be immediately set
}

[plainnany]

Mybe the following code is better.

record.dynaimc = {
  importee: [],
- runtimeName: `__matchRequireRuntime${counter}__`,
+ runtimeName: `__matchRequireRuntime${counter++}__`,
  runtimeFn: '', // to be immediately set
}

@yejimeiming counter++ may be used many times，consider using const counter3 = counter++ ？