Merge bitcoin/bitcoin#27667: ci: Remove unused errtrace trap ERR

fad09b703f ci: Remove unused errtrace trap ERR (MarcoFalke)

Pull request description:

  This was added in commit 069752b726, presumably at a time when the functional tests wouldn't capture stderr.

  Now that all tests capture and print stderr on failure, it can be removed. Reference:

  * Unit tests capture via `2>&1`:

  d7700d3a26/src/Makefile.test.include (L421)

  * Functional tests capture as well:

  d7700d3a26/test/functional/test_framework/test_node.py (L356)

ACKs for top commit:
  fanquake:
    ACK fad09b703f
  hebasto:
    ACK fad09b703f, tested on Ubuntu 22.04: I can still see warnings from the sanitizers in both unit and functional tests.

Tree-SHA512: 1e786eee432a7a50eb9f78b06b2b157321cc16f91b613e3b476e9e51572592fe4bcf4dc15df176e5f019f24497ac68cf332d2037b55b57498c93f4e19613163c

ci/test/06_script_b.sh

@@ -104,9 +104,6 @@ cd "${BASE_BUILD_DIR}/bitcoin-$HOST"
 
 bash -c "./configure --cache-file=../config.cache $BITCOIN_CONFIG_ALL $BITCOIN_CONFIG" || ( (cat config.log) && false)
 
-set -o errtrace
-trap 'bash -c "cat ${BASE_SCRATCH_DIR}/sanitizer-output/* 2> /dev/null"' ERR
-
 if [[ ${USE_MEMORY_SANITIZER} == "true" ]]; then
   # MemorySanitizer (MSAN) does not support tracking memory initialization done by
   # using the Linux getrandom syscall. Avoid using getrandom by undefining