Fix various pylint warnings in testing/tools/*.py

Remove unused imports, superfluous parenthesis, and fix wrong variable
names.

Change-Id: I5bced8678929275c9f2342da775685915429a9e8
Reviewed-on: https://pdfium-review.googlesource.com/c/pdfium/+/137893
Reviewed-by: Tom Sepez <tsepez@chromium.org>
Commit-Queue: Lei Zhang <thestig@chromium.org>
diff --git a/testing/tools/api_check.py b/testing/tools/api_check.py
index bea8845..55d911d 100755
--- a/testing/tools/api_check.py
+++ b/testing/tools/api_check.py
@@ -88,7 +88,7 @@
     functions = []
     functions_in_file = []
     for line in contents:
-      if (file_regex.match(line)):
+      if file_regex.match(line):
         functions.append(functions_in_file)
         functions_in_file = []
       match = chk_regex.match(line)
diff --git a/testing/tools/common.py b/testing/tools/common.py
index 80b7815..900e483 100755
--- a/testing/tools/common.py
+++ b/testing/tools/common.py
@@ -4,7 +4,6 @@
 # found in the LICENSE file.
 
 import datetime
-import glob
 import os
 import re
 import subprocess
diff --git a/testing/tools/fixup_pdf_template.py b/testing/tools/fixup_pdf_template.py
index 36369ba..eb36392 100755
--- a/testing/tools/fixup_pdf_template.py
+++ b/testing/tools/fixup_pdf_template.py
@@ -159,7 +159,7 @@
       for line in preprocessed:
         outfile.write(processor.process_line(line))
   except IOError:
-    print('failed to process %s' % input_path, file=sys.stderr)
+    print('failed to process %s' % infile, file=sys.stderr)
 
 
 def insert_includes(input_path, output_file, visited_set):
@@ -170,7 +170,7 @@
   visited_set.add(input_path)
   try:
     _, file_extension = os.path.splitext(input_path)
-    override_line_endings = (file_extension in EXTENSION_OVERRIDE_LINE_ENDINGS)
+    override_line_endings = file_extension in EXTENSION_OVERRIDE_LINE_ENDINGS
 
     end_of_file_line_ending = False
     with open(input_path, 'rb') as infile:
diff --git a/testing/tools/githelper.py b/testing/tools/githelper.py
index 19071b0..4333e6a 100644
--- a/testing/tools/githelper.py
+++ b/testing/tools/githelper.py
@@ -3,8 +3,6 @@
 # found in the LICENSE file.
 """Classes for dealing with git."""
 
-import subprocess
-
 from common import RunCommandPropagateErr
 
 
diff --git a/testing/tools/pngdiffer.py b/testing/tools/pngdiffer.py
index e61bc68..7411a82 100755
--- a/testing/tools/pngdiffer.py
+++ b/testing/tools/pngdiffer.py
@@ -8,7 +8,6 @@
 import os
 import shutil
 import subprocess
-import sys
 
 EXACT_MATCHING = 'exact'
 FUZZY_MATCHING = 'fuzzy'
diff --git a/testing/tools/safetynet_compare.py b/testing/tools/safetynet_compare.py
index 44061ad..a5e4f63 100755
--- a/testing/tools/safetynet_compare.py
+++ b/testing/tools/safetynet_compare.py
@@ -12,11 +12,9 @@
 import os
 import re
 import shutil
-import subprocess
 import sys
 import tempfile
 
-from common import GetBooleanGnArg
 from common import PrintErr
 from common import RunCommandPropagateErr
 from githelper import GitHelper