CI: speed up launch of heavy jobs (#34092)

Author: EugeniyKiyashko

.github/workflows/demos_unit_tests.yml

@@ -18,7 +18,7 @@ env:
 jobs:
   check-should-run:
     name: Check if tests should run
-    runs-on: devextreme-shr2
+    runs-on: ubuntu-latest
     outputs:
       should-run: ${{ steps.check.outputs.should-run }}
     steps:

.github/workflows/qunit_tests.yml

@@ -19,7 +19,7 @@ env:
 jobs:
   check-should-run-all:
     name: Check if all tests should run
-    runs-on: devextreme-shr2
+    runs-on: ubuntu-latest
     outputs:
       should-run: ${{ steps.check.outputs.should-run }}
     steps:

.github/workflows/visual-tests-demos.yml

@@ -19,7 +19,7 @@ env:
 jobs:
   check-should-run:
     name: Check if tests should run
-    runs-on: devextreme-shr2
+    runs-on: ubuntu-latest
     outputs:
       should-run: ${{ steps.check.outputs.should-run }}
     steps:
@@ -28,7 +28,7 @@ jobs:
         run: echo "should-run=${{ env.RUN_TESTS }}" >> $GITHUB_OUTPUT
 
   get-changes:
-    runs-on: devextreme-shr2
+    runs-on: ubuntu-latest
     needs: check-should-run
     if: github.event_name == 'pull_request' && needs.check-should-run.outputs.should-run == 'true'
     name: Get changed demos
@@ -73,7 +73,7 @@ jobs:
           retention-days: 1
 
   determine-framework-tests-scope:
-    runs-on: devextreme-shr2
+    runs-on: ubuntu-latest
     name: Determine scope for framework tests
     needs: [check-should-run, get-changes]
     if: |
@@ -1054,7 +1054,7 @@ jobs:
           if-no-files-found: ignore
 
   merge-artifacts:
-    runs-on: devextreme-shr2
+    runs-on: ubuntu-latest
     needs: [testcafe-jquery, testcafe-frameworks-all, testcafe-frameworks-changed]
     if: always() && (needs.testcafe-jquery.result == 'failure' || needs.testcafe-frameworks-all.result == 'failure' || needs.testcafe-frameworks-changed.result == 'failure')
 
@@ -1278,7 +1278,7 @@ jobs:
 
   csp-report-summary:
     name: CSP Violations Summary
-    runs-on: devextreme-shr2
+    runs-on: ubuntu-latest
     needs: [check-should-run, csp-check-jquery, csp-check-frameworks]
     if: always() && needs.check-should-run.outputs.should-run == 'true'
     timeout-minutes: 5