Merge #11435: build: Make "make clean" remove all files created when running "make...

Merge #11435: build: Make "make clean" remove all files created when running "make check"

f35d033 build: Make "make clean" remove all files created when running "make check" (practicalswift)

Pull request description:

  Make `make clean` remove all files created when running `make check`. More specifically: remove also `obj/build.h` and `bench/data/block413567.raw.h` as part of `make clean`.

  Before this patch:

  ```bash
  $ git clone https://github.com/bitcoin/bitcoin.git
  $ cd bitcoin/
  $ ./autogen.sh
  $ ./configure
  $ cp -r ../bitcoin ../bitcoin-before-make
  $ make check
  $ make clean
  $ cp -r ../bitcoin ../bitcoin-after-make-and-make-clean
  $ cd ..
  $ diff -rq bitcoin-before-make/ bitcoin-after-make-and-make-clean/ | grep -E "^Only in bitcoin-after-make-and-make-clean/" | grep -v dirstamp
  Only in bitcoin-after-make-and-make-clean/src/bench/data: block413567.raw.h
  Only in bitcoin-after-make-and-make-clean/src/obj: build.h
  $
  ```

  After this patch:

  ```bash
  $ git clone https://github.com/bitcoin/bitcoin.git
  $ cd bitcoin/
  $ ./autogen.sh
  $ ./configure
  $ cp -r ../bitcoin ../bitcoin-before-make
  $ make check
  $ make clean
  $ cp -r ../bitcoin ../bitcoin-after-make-and-make-clean
  $ cd ..
  $ diff -rq bitcoin-before-make/ bitcoin-after-make-and-make-clean/ | grep -E "^Only in bitcoin-after-make-and-make-clean/" | grep -v dirstamp
  $
  ```

Tree-SHA512: 953e8423485ffd415f0ade6abe0b4c407454f67c332140ef019d89db425bb4a831327b3f634b8d69b17325dcfc6e3ac72dc2ba1ce5462158eecc3c05645e93ba