mac: disable two more capture convert/scaling tests on mac-arm64

I missed disabling these when disabling failing mac-arm64 tests. They will be fixed
as part of fixing the linked bug.

Bug: 1154345
Change-Id: I344ad7adab1c8bde228ead069c2a9fa21a1d6dbc
Reviewed-on: https://chromium-review.googlesource.com/c/chromium/src/+/2575345Reviewed-by: Henrik Boström <hbos@chromium.org>
Commit-Queue: Elly Fong-Jones <ellyjones@chromium.org>
Cr-Commit-Position: refs/heads/master@{#833924}

media/capture/video/mac/sample_buffer_transformer_mac_unittest.mm

@@ -543,7 +543,7 @@ TEST_P(SampleBufferTransformerLibyuvTest, CanConvertFullScale) {
       PixelBufferIsSingleColor(output_pixel_buffer, kColorR, kColorG, kColorB));
 }
 
-TEST_P(SampleBufferTransformerLibyuvTest, CanConvertAndScaleDown) {
+TEST_P(SampleBufferTransformerLibyuvTest, MAYBE_CanConvertAndScaleDown) {
   OSType input_pixel_format;
   OSType output_pixel_format;
   std::tie(input_pixel_format, output_pixel_format) = GetParam();
@@ -673,7 +673,7 @@ TEST_P(SampleBufferTransformerMjpegTest, CanConvertFullScale) {
       PixelBufferIsSingleColor(output_pixel_buffer, kColorR, kColorG, kColorB));
 }
 
-TEST_P(SampleBufferTransformerMjpegTest, CanConvertAndScaleDown) {
+TEST_P(SampleBufferTransformerMjpegTest, MAYBE_CanConvertAndScaleDown) {
   OSType output_pixel_format = GetParam();
 
   base::ScopedCFTypeRef<CMSampleBufferRef> input_sample_buffer =