Merge bitcoin/bitcoin#31993: ci: use LLVM 20.1.0 for MSAN

d76647e ci: use LLVM 20.1.0 for MSAN (fanquake)

Pull request description:

  Now that the release is out, stop using rc1.

ACKs for top commit:
  l0rinc:
    utACK d76647e
  Sjors:
    ACK d76647e

Tree-SHA512: 2eefad118dd617c3e9554caee1549965fc4acc437dbef1252c1912faea57ccbfcb39f879911f27f4274931c1d8723b9c7f981aafa6958e70d4371f16c368c627

Author: fanquake

ci/test/01_base_install.sh

@@ -49,7 +49,7 @@ if [ -n "$PIP_PACKAGES" ]; then
 fi
 
 if [[ ${USE_MEMORY_SANITIZER} == "true" ]]; then
-  ${CI_RETRY_EXE} git clone --depth=1 https://github.com/llvm/llvm-project -b "llvmorg-20.1.0-rc1" /msan/llvm-project
+  ${CI_RETRY_EXE} git clone --depth=1 https://github.com/llvm/llvm-project -b "llvmorg-20.1.0" /msan/llvm-project
 
   cmake -G Ninja -B /msan/clang_build/ \
     -DLLVM_ENABLE_PROJECTS="clang" \