Merge bitcoin/bitcoin#22861: test: Update test README and lint script

fa0937de35176fdcf637e1af16be4469725e60cc test: Rename bitcoin-util-test.py to util/test_runner.py (MarcoFalke)
fa050bbc0ad479063735b0325daa717ded404c8f test: Update test README and lint script (MarcoFalke)

Pull request description:

  * Remove unused `yq`
  * Update fuzzing docs

ACKs for top commit:
  Saviour1001:
    ACK <code>[fa0937d](https://github.com/bitcoin/bitcoin/pull/22861/commits/fa0937de35176fdcf637e1af16be4469725e60cc)</code>
  practicalswift:
    cr ACK fa0937de35176fdcf637e1af16be4469725e60cc
  fanquake:
    ACK fa0937de35176fdcf637e1af16be4469725e60cc

Tree-SHA512: 6b148d838e1fcf219ab92e579948e34ea7ce8b4692a3d28bb2a51aaa34cbc7cdbd79e72ce787b485fdf524e5b3521b033692583602d4e379bd160e0e41d66e28

3 files changed, 9 insertions, 6 deletions

diff --git a/test/README.md b/test/README.md
index 51e61562a4..412d5ae106 100644
--- a/test/README.md
+++ b/test/README.md
@@ -5,20 +5,24 @@ etc.
 
 This directory contains the following sets of tests:
 
+- [fuzz](/test/fuzz) A runner to execute all fuzz targets from
+  [/src/test/fuzz](/src/test/fuzz).
 - [functional](/test/functional) which test the functionality of
 bitcoind and bitcoin-qt by interacting with them through the RPC and P2P
 interfaces.
-- [util](/test/util) which tests the bitcoin utilities, currently only
-bitcoin-tx.
+- [util](/test/util) which tests the utilities (bitcoin-util, bitcoin-tx, ...).
 - [lint](/test/lint/) which perform various static analysis checks.
 
-The util tests are run as part of `make check` target. The functional
+The util tests are run as part of `make check` target. The fuzz tests, functional
 tests and lint scripts can be run as explained in the sections below.
 
 # Running tests locally
 
 Before tests can be run locally, Bitcoin Core must be built.  See the [building instructions](/doc#building) for help.
 
+## Fuzz tests
+
+See [/doc/fuzzing.md](/doc/fuzzing.md)
 
 ### Functional tests
 
@@ -257,7 +261,7 @@ For ways to generate more granular profiles, see the README in
 
 ### Util tests
 
-Util tests can be run locally by running `test/util/bitcoin-util-test.py`.
+Util tests can be run locally by running `test/util/test_runner.py`.
 Use the `-v` option for verbose output.
 
 ### Lint tests
@@ -269,7 +273,6 @@ Use the `-v` option for verbose output.
 | [`lint-python.sh`](lint/lint-python.sh) | [flake8](https://gitlab.com/pycqa/flake8) | [3.8.3](https://github.com/bitcoin/bitcoin/pull/19348) | `pip3 install flake8==3.8.3`
 | [`lint-python.sh`](lint/lint-python.sh) | [mypy](https://github.com/python/mypy) | [0.781](https://github.com/bitcoin/bitcoin/pull/19348) | `pip3 install mypy==0.781`
 | [`lint-shell.sh`](lint/lint-shell.sh) | [ShellCheck](https://github.com/koalaman/shellcheck) | [0.7.2](https://github.com/bitcoin/bitcoin/pull/21749) | [details...](https://github.com/koalaman/shellcheck#installing)
-| [`lint-shell.sh`](lint/lint-shell.sh) | [yq](https://github.com/kislyuk/yq) | default | `pip3 install yq`
 | [`lint-spelling.sh`](lint/lint-spelling.sh) | [codespell](https://github.com/codespell-project/codespell) | [2.0.0](https://github.com/bitcoin/bitcoin/pull/20817) | `pip3 install codespell==2.0.0`
 
 Please be aware that on Linux distributions all dependencies are usually available as packages, but could be outdated.
diff --git a/test/config.ini.in b/test/config.ini.in
index e3872181cd..db80bba6f1 100644
--- a/test/config.ini.in
+++ b/test/config.ini.in
@@ -3,7 +3,7 @@
 # file COPYING or http://www.opensource.org/licenses/mit-license.php.
 
 # These environment variables are set by the build process and read by
-# test/functional/test_runner.py and test/util/bitcoin-util-test.py
+# test/*/test_runner.py and test/util/rpcauth-test.py
 
 [environment]
 PACKAGE_NAME=@PACKAGE_NAME@
diff --git a/test/util/bitcoin-util-test.py b/test/util/test_runner.py
index aa8fd6eee5..aa8fd6eee5 100755
--- a/test/util/bitcoin-util-test.py
+++ b/test/util/test_runner.py