ci: twister: fix result merge when there's only 1 runner

The current test result merge command uses artifacts/*/*/twister.xml as
an argument but that directory hierarchy only works if there's >1
runners. If twister decies to only schedule one, then the only file is
going to be in

artifacts/twister-out/twister.xml

and the current command is going to fail with a file not found error.

Using a ** glob for finding the files.

Signed-off-by: Fabio Baltieri <[email protected]>

Author: fabiobaltieri

.github/workflows/clang.yaml

@@ -159,7 +159,7 @@ jobs:
 
       - name: Merge Test Results
         run: |
-          junitparser merge artifacts/*/twister.xml junit.xml
+          junitparser merge --glob artifacts/**/twister.xml junit.xml
           junit2html junit.xml junit-clang.html
 
       - name: Upload Unit Test Results in HTML

.github/workflows/twister.yaml

@@ -347,7 +347,7 @@ jobs:
 
       - name: Merge Test Results
         run: |
-          junitparser merge artifacts/*/*/twister.xml junit.xml
+          junitparser merge --glob artifacts/**/twister.xml junit.xml
           junit2html junit.xml junit.html
 
       - name: Upload Unit Test Results