[release/7.0] Target lower glibc for Linux arm64 (#80866)

* Target lower glibc for Linux arm64

* Update crossrootfsDir

* Set prefix for mono

* Revert "Update crossrootfsDir"

This reverts commit 8fee6ff.

* Update image version

Author: sbomer

eng/pipelines/common/platform-matrix.yml

@@ -95,7 +95,7 @@ jobs:
       shouldContinueOnError: ${{ parameters.shouldContinueOnError }}
       container:
         ${{ if eq(parameters.container, '') }}:
-          image: ubuntu-18.04-cross-arm64-20220427171722-6e40d49
+          image: ubuntu-20.04-cross-arm64-20230201170357-8b7d579
         ${{ if ne(parameters.container, '') }}:
           image: ${{ parameters.container }}
         registry: mcr

src/mono/mono.proj

@@ -632,6 +632,7 @@
       <MonoAotAbi>aarch64-linux-gnu</MonoAotAbi>
       <MonoAotOffsetsFile>$(MonoObjCrossDir)offsets-aarch-linux-gnu.h</MonoAotOffsetsFile>
       <MonoAotOffsetsPrefix>$(MonoCrossDir)/usr/lib/gcc/aarch64-linux-gnu/7</MonoAotOffsetsPrefix>
+      <MonoAotOffsetsPrefix Condition="'$(Platform)' == 'arm64'">$(MonoCrossDir)/usr/lib/gcc/aarch64-linux-gnu/5</MonoAotOffsetsPrefix>
     </PropertyGroup>
 
     <!-- macOS host specific options -->