Revert "Add expectations.txt validation to presubmit"

This reverts commit cde5589.

Reason for revert: Script fails on Windows.

Original change's description:
> Add expectations.txt validation to presubmit
>
> Change-Id: Ibabdfbdf44b027a6e6441e140f23b2c2488f32dc
> Reviewed-on: https://dawn-review.googlesource.com/c/dawn/+/112120
> Reviewed-by: Ben Clayton <[email protected]>
> Commit-Queue: Austin Eng <[email protected]>
> Kokoro: Kokoro <[email protected]>

# Not skipping CQ checks because original CL landed > 1 day ago.

Change-Id: I106ab755af5fde289c0d014bf3be77d93dfd0beb
Reviewed-on: https://dawn-review.googlesource.com/c/dawn/+/112400
Commit-Queue: Ben Clayton <[email protected]>
Reviewed-by: Ben Clayton <[email protected]>
Kokoro: Austin Eng <[email protected]>
Commit-Queue: Austin Eng <[email protected]>
Auto-Submit: Austin Eng <[email protected]>

go_presubmit_support.py

@@ -12,24 +12,17 @@
 # See the License for the specific language governing permissions and
 # limitations under the License.
 
-
-def go_path(input_api):
-    go = input_api.os_path.join(input_api.change.RepositoryRoot(), "tools",
-                                "golang", "bin", "go")
-    if input_api.is_windows:
-        go += '.exe'
-
-    return go
-
-
 def RunGoTests(input_api, output_api):
     results = []
     try:
-        input_api.subprocess.check_call_out(
-            [go_path(input_api), "test", "./..."],
-            stdout=input_api.subprocess.PIPE,
-            stderr=input_api.subprocess.PIPE,
-            cwd=input_api.PresubmitLocalPath())
+        go = input_api.os_path.join(input_api.change.RepositoryRoot(), "tools",
+                                    "golang", "bin", "go")
+        if input_api.is_windows:
+            go += '.exe'
+        input_api.subprocess.check_call_out([go, "test", "./..."],
+                                            stdout=input_api.subprocess.PIPE,
+                                            stderr=input_api.subprocess.PIPE,
+                                            cwd=input_api.PresubmitLocalPath())
     except input_api.subprocess.CalledProcessError as e:
         results.append(output_api.PresubmitError('%s' % (e, )))
     return results