boards/common/stdio_tinyusb_cdc_acm: let tests wait for serial port

After a reset, it can take several seconds before the CDC ACM interface becomes available as serial device `ttyACMx`. This was a change that was already made for `stdio_cdc_acm` in #19128.

boards/common/makefiles/stdio_tinyusb_cdc_acm.dep.mk

@@ -8,4 +8,9 @@ ifeq (,$(filter stdio_% slipdev_stdio,$(USEMODULE)))
   endif
 
   FEATURES_REQUIRED += highlevel_stdio
+
+  # Enforce tests to wait a bit for the serial port after reset
+  TERM_DELAY ?= 2
+  TESTRUNNER_CONNECT_DELAY ?= $(TERM_DELAY)
+  $(call target-export-variables,test,TESTRUNNER_CONNECT_DELAY)
 endif