Merge bitcoin/bitcoin#33555: build: Bump clang minimum supported version to 17

fa0fa0f700 refactor: Revert "disable self-assign warning for tests" (MarcoFalke)
faed118fb3 build: Bump clang minimum supported version to 17 (MarcoFalke)

Pull request description:

  Most supported operating systems ship with clang-17 (or later), so bump the minimum to that and allow new code to drop workarounds for previous clang bugs.

  (Apart from dropping the small workaround, this bump allows the `ci_native_nowallet_libbitcoinkernel` CI to run on riscv64 without running into an ICE with clang-16.)

  This patch will only be released in version 31.x, next year (2026).

  For reference:

  * https://packages.debian.org/bookworm/clang-19
  * https://packages.ubuntu.com/noble/clang (clang-18)
  * CentOS-like 8/9/10 ship clang-17 (and later) via Stream
  * FreeBSD 12/13 ship clang-17 (and later) via packages
  * OpenSuse Tumbleweed ships with https://software.opensuse.org/package/clang (clang21); No idea about OpenSuse Leap

  On operating systems where the clang version is not shipped by default, the user would have to use GCC, or install clang in a different way. For example:

  * https://packages.debian.org/bookworm/g++ (g++-12)
  * https://packages.ubuntu.com/jammy/g++ (g++-11)
  * https://apt.llvm.org/, or nix, or guix, or compile clang from source, ...

  *Ubuntu 22.04 LTS does not ship with clang-16 (the previous minimum required), nor with clang-17, so one of the above workarounds is needed there.*

  macOS 14 is unaffected, and the previous minimum requirement of Xcode15.0 remains, see also 919e6d01e9/depends/hosts/darwin.mk (L3-L4). (Modulo compiling the fuzz tests, which requires 919e6d01e9/.github/workflows/ci.yml (L149))

ACKs for top commit:
  janb84:
    Concept ACK fa0fa0f700
  l0rinc:
    Code review ACK fa0fa0f700
  hebasto:
    ACK fa0fa0f700.

Tree-SHA512: 5973cec39982f80b8b43e493cde012d9d1ab75a0362300b007d155db9f871c6341e7e209e5e63f0c3ca490136b684683de270136d62cb56f6b00b0ac0331dc36

src/test/fuzz/muhash.cpp

@@ -199,19 +199,7 @@ FUZZ_TARGET(muhash)
         },
         [&] {
             // Test that dividing a MuHash by itself brings it back to its initial state
-
-            // See note about clang + self-assignment in test/uint256_tests.cpp
-            #if defined(__clang__)
-            #    pragma clang diagnostic push
-            #    pragma clang diagnostic ignored "-Wself-assign-overloaded"
-            #endif
-
             muhash /= muhash;
-
-            #if defined(__clang__)
-            #    pragma clang diagnostic pop
-            #endif
-
             muhash.Finalize(out);
             out2 = initial_state_hash;
         },