fix(compiler-sfc): properly handle assignment expressions with local vars in inline mode

[edison1105]

fix #4514

[lidlanca]

consider an additional test for the "local variable" in template, which is not explicitly
covered by the assignment fix test case

  test('template local variable', ()=>{
    const { content } = compile(
      `<script setup>
      import {ref} from "vue"
      const v = ref()
      </script>
      <template>
        <div @click="(e) => {
          let a = 1 
          const b = a
          var c = b
          (a,b,c,d,e)  // all local

          // nested scopes
          (()=>{
            let x = a
            (()=>{
              let z = x
              let z2 = z
            })
            let fromNonLocalZ = z // _ctx is expected
          })        
          v = a
          var d = 4
      }"/>

      </template>
      `,
      { inlineTemplate: true }
    )
    assertCode(content)
  })