Co-authored-by: zeertzjq <zeertzjq@outlook.com>

Problem:    Vim9: script reload test is disabled.
Solution:   Compile a function in the context of the script where it was
            defined.  Set execution stack for compiled function.  Add a test
            that an error is reported for the right file/function.
https://github.com/vim/vim/commit/25e0f5863e9010a75a1ff0d04e8f886403968755

Omit stack_top_is_ufunc(): only used by Vim9 script.

Problem:    Expanding <sfile> works differently the second time.
Solution:   Keep the expanded name when redefining a function. (closes vim/vim#5425)
https://github.com/vim/vim/commit/b9adef79eca6f95bc7376ff3a6a383e436c5d6ea

Problem:    Execution stack is incomplete and inefficient.
Solution:   Introduce a proper execution stack and use it instead of
            sourcing_name/sourcing_lnum.  Create a string only when used.
https://github.com/vim/vim/commit/1a47ae32cdc19b0fd5a82e19fe5fddf45db1a506

Omit test_debugger.vim: superseded by later patches.
Omit check_map_keycodes(): N/A.
Omit kword_test.c: N/A (converted to a unit test).

Mostly avoids including eval.h, ex_cmds2.h and ex_docmd.h in other
headers.

Work on https://github.com/neovim/neovim/issues/459

This avoids including ex_eval.h in any other header, thus preventing
future circular includes.

Problem:    Profiling code is spread out.
Solution:   Move more profiling code to profiler.c. (Yegappan Lakshmanan,
            closes vim/vim#4668)
https://github.com/vim/vim/commit/660a10ad41c14363326f83451c3c425201923119

Problem:    Profiling functionality is spread out.
Solution:   Put profiling functionality in profiling.c. (Yegappan Lakshmanan,
            closes vim/vim#4666)
https://github.com/vim/vim/commit/fa55cfc69d2b14761e2a8bd85bc1e0d82df770aa

Move proftime_T to types.h for now to avoid recursive #include.

vim-patch:8.2.0559: clearing a struct is verbose

Problem:    Clearing a struct is verbose.
Solution:   Define and use CLEAR_FIELD() and CLEAR_POINTER().
https://github.com/vim/vim/commit/a80faa8930ed5a554beeb2727762538873135e83