Make autotest java test filter more robust

Fix autotest so autotest.py -C <dir> /CurrentPageVerifierTest.java won't
run tests for other classes like WebApkCurrentPageVerifierTest

Change-Id: I0370b507ac21009676d9e27c109b90d7223b7ab9
Reviewed-on: https://chromium-review.googlesource.com/c/chromium/src/+/2419267
Auto-Submit: Michael Thiessen <mthiesse@chromium.org>
Commit-Queue: Andrew Grieve <agrieve@chromium.org>
Reviewed-by: Andrew Grieve <agrieve@chromium.org>
Cr-Commit-Position: refs/heads/master@{#808645}

tools/autotest.py

@@ -330,7 +330,7 @@ def BuildCppTestFilter(filenames, line):
 
 
 def BuildJavaTestFilter(filenames):
-  return ':'.join('*{}*'.format(os.path.splitext(os.path.basename(f))[0])
+  return ':'.join('*.{}*'.format(os.path.splitext(os.path.basename(f))[0])
                   for f in filenames)