[posix] enable expect tests on macOS (#5384)

This commit enables expect tests on macOS, also includes the following
required changes:

* Fixed bound to interface issue on macOS.
* Added ability to configure scan period, because macOS environment on
  GitHub Actions is much slower.

tests/scripts/expect/_common.exp

@@ -27,8 +27,15 @@
 #  POSSIBILITY OF SUCH DAMAGE.
 #
 
+proc skip_on_macos {} {
+    set OSTYPE [lindex $::tcl_platform(os) 0]
+
+    if { $OSTYPE == "Darwin" } {
+        exit 77
+    }
+}
+
 proc wait_for {command success {failure {[\r\n]FAILURE_NOT_EXPECTED[\r\n]}}} {
-    set result 0
     set timeout 1
     for {set i 0} {$i < 20} {incr i} {
         if {$command != ""} {
@@ -37,22 +44,17 @@ proc wait_for {command success {failure {[\r\n]FAILURE_NOT_EXPECTED[\r\n]}}} {
 
         expect {
             -re $success {
-                set result 1
+                return 0
             }
             -re $failure {
-                error "Got failure in wait_for"
+                fail "Failed due to '$failure' found"
             }
             timeout {
                 # Do nothing
             }
         }
-        if {$result == 1} {
-            break
-        }
-    }
-    if {$result == 0} {
-        error "Timed out in wait_for"
     }
+    fail "Failed due to '$success' not found"
 }
 
 proc expect_line {line} {
@@ -107,7 +109,7 @@ proc spawn_node {id {type ""} {radio_url ""}} {
     }
 
     expect_after {
-        timeout { error "Timed out" }
+        timeout { fail "Timed out" }
     }
 
     set spawn_ids($id) $spawn_id
@@ -123,12 +125,6 @@ proc switch_node {id} {
     set spawn_id $spawn_ids($id)
 }
 
-proc dispose_node {id} {
-    switch_node $id
-    send "\x04"
-    expect eof
-}
-
 proc setup_leader {} {
     send "dataset init new\n"
     expect_line "Done"
@@ -144,6 +140,12 @@ proc setup_leader {} {
     expect_line "Done"
 }
 
+proc dispose_node {id} {
+    switch_node $id
+    send "\x04"
+    expect eof
+}
+
 proc dispose_all {} {
     global spawn_ids
     set max_node [array size spawn_ids]
@@ -188,4 +190,9 @@ proc setup_default_network {} {
     expect_line "Done"
 }
 
+proc fail {message} {
+    dispose_all
+    error $message
+}
+
 set timeout 10