iOS jobs failing in official builds

[jaredpar]

Rough build error

  Commencing build of "native libraries component" for iOS.arm.Release in /Users/runner/runners/2.165.2/work/1/s/artifacts/obj/native/netcoreapp5.0-iOS-Release-arm
    Determining projects to restore...
    Restored /Users/runner/runners/2.165.2/work/1/s/eng/empty.csproj (in 635 ms).
  Invoking "/Users/runner/runners/2.165.2/work/1/s/eng/native/gen-buildsys.sh" "/Users/runner/runners/2.165.2/work/1/s/src/libraries/Native/Unix" "/Users/runner/runners/2.165.2/work/1/s/src/libraries/Native/Unix" "/Users/runner/runners/2.165.2/work/1/s/artifacts/obj/native/netcoreapp5.0-iOS-Release-arm" arm clang "" "" Release ""  -DCLR_ENG_NATIVE_DIR="/Users/runner/runners/2.165.2/work/1/s/eng/native" -DCMAKE_OSX_SYSROOT=iphoneos -DCMAKE_OSX_DEPLOYMENT_TARGET=7.0 -DCMAKE_OSX_ARCHITECTURES="armv7;armv7s" -DCMAKE_SYSTEM_NAME=iOS 
  CMake Warning at /usr/local/Cellar/cmake/3.17.0_1/share/cmake/Modules/Platform/Darwin-Initialize.cmake:204 (message):
    No SDK found for architecture 'armv7'
  Call Stack (most recent call first):
    /usr/local/Cellar/cmake/3.17.0_1/share/cmake/Modules/Platform/Darwin-Initialize.cmake:213 (_apple_resolve_multi_arch_sysroots)
    /usr/local/Cellar/cmake/3.17.0_1/share/cmake/Modules/Platform/iOS-Initialize.cmake:1 (include)
    /usr/local/Cellar/cmake/3.17.0_1/share/cmake/Modules/CMakeSystemSpecificInitialize.cmake:21 (include)
    CMakeLists.txt:4 (project)
  
  
  CMake Warning at /usr/local/Cellar/cmake/3.17.0_1/share/cmake/Modules/Platform/Darwin-Initialize.cmake:204 (message):
    No SDK found for architecture 'armv7s'
  Call Stack (most recent call first):
    /usr/local/Cellar/cmake/3.17.0_1/share/cmake/Modules/Platform/Darwin-Initialize.cmake:213 (_apple_resolve_multi_arch_sysroots)
    /usr/local/Cellar/cmake/3.17.0_1/share/cmake/Modules/Platform/iOS-Initialize.cmake:1 (include)
    /usr/local/Cellar/cmake/3.17.0_1/share/cmake/Modules/CMakeSystemSpecificInitialize.cmake:21 (include)
    CMakeLists.txt:4 (project)
  
  
  -- The C compiler identification is AppleClang 11.0.0.11000033
  -- Check for working C compiler: /Applications/Xcode_11.3.1.app/Contents/Developer/Toolchains/XcodeDefault.xctoolchain/usr/bin/clang
  Failed to generate "native libraries component" build project!

Build	Kind	Timeline Record
587441	Rolling	Prepare testhost folder to publish
587369	Rolling	Prepare testhost folder to publish
587257	Rolling	Prepare testhost folder to publish
586799	Rolling	Prepare testhost folder to publish

Evaluated 50 builds
Impacted 4 bulids
Impacted 4 jobs

runfo search-timeline -d runtime-official -c 50 -v "Not found SourceFolder" -m

Note: The SourceFolder message is not the exact error, but a consequence of the earlier error. The actual build error has a variety of error messages and gets clipped by AzDO in a few cases. Eventually had to use this query instead but it's getting the right builds.

Tagging @ViktorHofer as an area owner

[jaredpar]

dupe of #34465