Support SFC name inference

[Marsel Shayhin]

name should be inferred based on file name.
It may also be a good idea to use file paths as part of name (@/foo/bar.vue -> name: 'FooBar', but the spec has no such requirement.

Spec:
https://github.com/vuejs/core/blob/272ab9fbdcb1af0535108b9f888e80d612f9171d/packages/compiler-sfc/__tests__/compileScript.spec.ts#L1252-L1306