tests: Add test for riscvmatched-hello stdlib example

This test ensures the example script is still functioning and, by proxy,
does a simple test to ensure the riscvmatched board's SE workload
capabilities are still working.

Change-Id: I7c79856e84122c6737e1e9667b6e626b4622d04c
Reviewed-on: https://gem5-review.googlesource.com/c/public/gem5/+/63591
Maintainer: Jason Lowe-Power <power.jg@gmail.com>
Tested-by: kokoro <noreply+kokoro@google.com>
Reviewed-by: Jason Lowe-Power <power.jg@gmail.com>

tests/gem5/gem5_library_example_tests/test_gem5_library_examples.py

@@ -243,3 +243,20 @@ gem5_verify_config(
     valid_hosts=constants.supported_hosts,
     length=constants.long_tag,
 )
+
+gem5_verify_config(
+    name="test-gem5-library-example-riscvmatched-hello",
+    fixtures=(),
+    verifiers=(),
+    config=joinpath(
+        config.base_dir,
+        "configs",
+        "example",
+        "gem5_library",
+        "riscvmatched-hello.py",
+    ),
+    config_args=[],
+    valid_isas=(constants.riscv_tag,),
+    valid_hosts=constants.supported_hosts,
+    length=constants.long_tag,
+)