Bug 1831512 [wpt PR 39861] - Remove use of deprecated imp module, a=testonly

Automatic update from web-platform-tests
Remove use of deprecated imp module

This was being used to load browser modules from a path specified in a
config file. That would presumably allow vendors to define an
out-of-tree browser module. But in practice vendors are defining the
browser modules in-tree (and it would be very difficult to define a
browser out of tree without suffering frequent breakage). So since imp
is deprecated just remove the entire feature.

wpt-commits: 67699587804dfd8b77b77eb528f155a42e14906b
wpt-pr: 39861


diff --git a/testing/web-platform/tests/tools/wptrunner/wptrunner/products.py b/testing/web-platform/tests/tools/wptrunner/wptrunner/products.py
--- a/testing/web-platform/tests/tools/wptrunner/wptrunner/products.py
+++ b/testing/web-platform/tests/tools/wptrunner/wptrunner/products.py
@@ -1,26 +1,19 @@
 # mypy: allow-untyped-defs
-
 import importlib
-import imp
 
 from .browsers import product_list
 
 
 def product_module(config, product):
     if product not in product_list:
         raise ValueError("Unknown product %s" % product)
 
-    path = config.get("products", {}).get(product, None)
-    if path:
-        module = imp.load_source('wptrunner.browsers.' + product, path)
-    else:
-        module = importlib.import_module("wptrunner.browsers." + product)
-
+    module = importlib.import_module("wptrunner.browsers." + product)
     if not hasattr(module, "__wptrunner__"):
         raise ValueError("Product module does not define __wptrunner__ variable")
 
     return module
 
 
 class Product:
     def __init__(self, config, product):