[libc++] [WIP] Add metrics collection for libc++ premerge testing.

** DRAFT!! DO NOT REVIEW! DO NOT MERGE! **

Work-in-progress, playing around with adding metrics collection
and dashboard for libc++ premerge testing data.

Author: cmtice

.github/workflows/libcxx-build-and-test.yaml

@@ -35,6 +35,7 @@ concurrency:
 
 jobs:
   stage1:
+    name: libc++ Stage1 Testing
     if: github.repository_owner == 'llvm'
     runs-on: llvm-premerge-libcxx-runners
     continue-on-error: false
@@ -72,6 +73,7 @@ jobs:
             **/CMakeOutput.log
             **/crash_diagnostics/*
   stage2:
+    name: libc++ Stage2 Testing
     if: github.repository_owner == 'llvm'
     runs-on: llvm-premerge-libcxx-runners
     needs: [ stage1 ]
@@ -117,6 +119,7 @@ jobs:
             **/CMakeOutput.log
             **/crash_diagnostics/*
   stage3:
+    name: libc++ Stage3 Testing
     if: github.repository_owner == 'llvm'
     needs: [ stage2 ]
     continue-on-error: false