Turn off CoreFX test legs in CI.

Now that the branch is on servicing, and the churn is low, exclude these as they
break far more often than they detect issues. These already run in CoreFX CI on release bits.
In case we want to bring them back for checked testing, we need to fix CoreFX.depproj.
It has a package - Microsoft.Private.CoreFx.OOB - that's supposed to bring in all deps
that are out of box. These are currently not getting restored and this ends up causing
File not found issues in the binder when compiling tests, making test exclusions impossible.
Please enter the commit message for your changes. Lines starting
with '#' will be ignored, and an empty message aborts the commit.

Author: hoyosjs

eng/pipelines/pr.yml

@@ -93,19 +93,24 @@ jobs:
 
 #
 # CoreFX test runs against CoreCLR
-#
-- template: /eng/platform-matrix.yml
-  parameters:
-    jobTemplate: test-job.yml
-    buildConfig: checked
-    platforms:
-    - Linux_x64
-    - Windows_NT_x64
-    helixQueueGroup: pr
-    jobParameters:
-      testGroup: innerloop
-      corefxTests: true
-      displayNameArgs: CoreFX
+# Now that the branch is on servicing, and the churn is low, exclude these as they
+# break far more often than they detect issues. These already run in CoreFX CI on release bits.
+# In case we want to bring them back for checked testing, we need to fix CoreFX.depproj.
+# It has a package - Microsoft.Private.CoreFx.OOB - that's supposed to bring in all deps
+# that are out of box. These are currently not getting restored and this ends up causing 
+# File not found issues in the binder when compiling tests, making test exclusions impossible.
+# - template: /eng/platform-matrix.yml
+#   parameters:
+#     jobTemplate: test-job.yml
+#     buildConfig: checked
+#     platforms:
+#     - Linux_x64
+#     - Windows_NT_x64
+#     helixQueueGroup: pr
+#     jobParameters:
+#       testGroup: innerloop
+#       corefxTests: true
+#       displayNameArgs: CoreFX
 
 #
 # Release test builds