Tests: Move GPU vendor query function to module, remove dead code for EEVEE

The implementation of this was broken and not actually used for the EEVEE
tests, as there is currently no separate reference directory for AMD.

Move it to the render report module so it can be reused by different tests.

Pull Request: https://projects.blender.org/blender/blender/pulls/148148

tests/python/modules/render_report.py

@@ -174,6 +174,25 @@ def diff_output(test, oiiotool, fail_threshold, fail_percent, verbose, update):
     return test
 
 
+def get_gpu_device_vendor(blender):
+    command = [
+        blender,
+        "--background",
+        "--factory-startup",
+        "--python",
+        str(pathlib.Path(__file__).parent / "gpu_info.py")
+    ]
+    try:
+        completed_process = subprocess.run(command, stdout=subprocess.PIPE, universal_newlines=True)
+        for line in completed_process.stdout.splitlines():
+            if line.startswith("GPU_DEVICE_TYPE:"):
+                vendor = line.split(':')[1].upper()
+                return vendor
+    except Exception:
+        return None
+    return None
+
+
 class Report:
     __slots__ = (
         'title',