Make isolate_driver.py only add .dll/.so/.dylib for component builds' generated files.

Right now it's adding a lot of other files that aren't needed to run the tests, which slows down the uploading and downloading steps when using component builds. Since this preprocessing step is only meant to add extra binaries that are the result of the component build, just whitelist .dll/.so/.dylib.

BUG=414808

Review URL: https://codereview.chromium.org/592143002

Cr-Commit-Position: refs/heads/master@{#296037}

tools/isolate_driver.py

@@ -177,6 +177,12 @@ def post_process_deps(build_dir, dependencies):
     return i
 
   def f(i):
+    # This script is only for adding new binaries that are created as part of
+    # the component build.
+    ext = os.path.splitext(i)[1]
+    if ext not in ['.dll', '.so', '.dylib']:
+      return False
+
     # Check for execute access and strip directories. This gets rid of all the
     # phony rules.
     p = os.path.join(build_dir, i)