Remove llvm-toolchain-focal-9 dependency (#2721)

Author: ViktorHofer

.vsts-ci-official.yml

@@ -149,10 +149,6 @@ extends:
             steps:
             - checkout: self
               clean: true
-            - bash: |
-                wget -O - https://apt.llvm.org/llvm-snapshot.gpg.key | sudo apt-key add -
-                sudo apt-add-repository "deb https://apt.llvm.org/focal/ llvm-toolchain-focal-9 main"
-                sudo apt-get update
             - bash: |
                 sudo apt-get install cmake clang-9 libicu66 uuid-dev libcurl4-openssl-dev zlib1g-dev libkrb5-dev
             - script: eng/common/cibuild.sh

.vsts-ci.yml

@@ -93,10 +93,6 @@ stages:
         steps:
         - checkout: self
           clean: true
-        - bash: |
-            wget -O - https://apt.llvm.org/llvm-snapshot.gpg.key | sudo apt-key add -
-            sudo apt-add-repository "deb https://apt.llvm.org/focal/ llvm-toolchain-focal-9 main"
-            sudo apt-get update
         - bash: |
             sudo apt-get install cmake clang-9 libicu66 uuid-dev libcurl4-openssl-dev zlib1g-dev libkrb5-dev
         - script: eng/common/cibuild.sh