Improve interface between compiler and symtable

In this issue I want to try and improve the interface between the compiler and the symtable.

Problems I see are:

• the compiler modifies the symtable
• the compiler performs calculations that the symtable could do (such as in push_inlined_comprehension_state)
• the symtable is actually not a correct representation of some scopes, like those of inlined comprehensions (the comprehension scope it removed from the symtable tree, but is still access from the compiler via the symtable dict). Exception handlers are another example of scope changes that the compiler does, which are not reflected in the symtable.

Linked PRs

• gh-122986

首先閱讀 compiler 和 symtable 的實作，重點關注 push_inlined_comprehension_state，以及對 inlined comprehensions 和例外處理常式的處理。完成的標準是建立一個更清晰的介面，使 compiler 不修改 symtable，將由 symtable 負責的計算移到其中，並以一致的方式表示作用域變更。