net/android/tools/proxy_test_cases.py: Convert uses of has_key

Conversion performed automatically using '2to3 -w -f has_key .'.
This is backwards compatible with Python 2.

Bug: 941669
Change-Id: I0fa85094d653173d14d8b7a63e3d5120397fd5f0
Reviewed-on: https://chromium-review.googlesource.com/c/chromium/src/+/1814927
Auto-Submit: Raul Tambre <raul@tambre.ee>
Commit-Queue: Matt Menke <mmenke@chromium.org>
Reviewed-by: Matt Menke <mmenke@chromium.org>
Cr-Commit-Position: refs/heads/master@{#698893}

net/android/tools/proxy_test_cases.py

@@ -311,7 +311,7 @@ class GenerateJava:
 
   def Generate(self):
     for test_case in test_cases:
-      if test_case.has_key("cpp-only"):
+      if "cpp-only" in test_case:
         continue
       if "description" in test_case:
         self._GenerateDescription(test_case["description"]);