[concurrency] Disable custom executor tests on Windows since they seem to hang.

Custom executor isn't a true feature yet, so I am disabling on Windows until we
can look at why the hangs are occuring on Windows.

(cherry picked from commit dae605a)

Author: gottesmm

test/Concurrency/Runtime/custom_executors.swift

@@ -7,6 +7,9 @@
 // UNSUPPORTED: back_deployment_runtime
 // UNSUPPORTED: use_os_stdlib
 
+// Disabled until test hang can be looked at.
+// UNSUPPORTED: OS=windows-msvc
+
 actor Simple {
   var count = 0
   func report() {

test/Concurrency/Runtime/exclusivity_custom_executors.swift

@@ -7,6 +7,9 @@
 // UNSUPPORTED: back_deployment_runtime
 // UNSUPPORTED: use_os_stdlib
 
+// Disabled until test hang can be looked at.
+// UNSUPPORTED: OS=windows-msvc
+
 // This test makes sure that we properly save/restore access when we
 // synchronously launch a task from a serial executor. The access from the task
 // should be merged into the already created access set while it runs and then

test/Concurrency/Runtime/exclusivity_custom_executors_filecheck.swift

@@ -7,6 +7,9 @@
 // UNSUPPORTED: back_deployment_runtime
 // UNSUPPORTED: use_os_stdlib
 
+// Disabled until test hang can be looked at.
+// UNSUPPORTED: OS=windows-msvc
+
 // Only enabled if our stdlib has asserts enabled since the exclusivity runtime
 // will only emit logging when the stdlib is compiled with asserts. This is done
 // on purpose since we do not want to ship the runtime with this logging even