Remove deadcode (#22245)

- Remove code that isn't being used.

Found this is my stash from a few weeks ago, not sure how I found this
in the first place.

Co-authored-by: Lunny Xiao <xiaolunwen@gmail.com>

modules/git/repo_attribute_test.go

@@ -95,64 +95,3 @@ func Test_nulSeparatedAttributeWriter_ReadAttribute(t *testing.T) {
 		Value:     "unspecified",
 	}, attr)
 }
-
-func Test_lineSeparatedAttributeWriter_ReadAttribute(t *testing.T) {
-	wr := &lineSeparatedAttributeWriter{
-		attributes: make(chan attributeTriple, 5),
-	}
-
-	testStr := `".gitignore\"\n": linguist-vendored: unspecified
-`
-	n, err := wr.Write([]byte(testStr))
-
-	assert.Equal(t, n, len(testStr))
-	assert.NoError(t, err)
-
-	select {
-	case attr := <-wr.ReadAttribute():
-		assert.Equal(t, ".gitignore\"\n", attr.Filename)
-		assert.Equal(t, "linguist-vendored", attr.Attribute)
-		assert.Equal(t, "unspecified", attr.Value)
-	case <-time.After(100 * time.Millisecond):
-		assert.Fail(t, "took too long to read an attribute from the list")
-	}
-
-	// Write a second attribute again
-	n, err = wr.Write([]byte(testStr))
-
-	assert.Equal(t, n, len(testStr))
-	assert.NoError(t, err)
-
-	select {
-	case attr := <-wr.ReadAttribute():
-		assert.Equal(t, ".gitignore\"\n", attr.Filename)
-		assert.Equal(t, "linguist-vendored", attr.Attribute)
-		assert.Equal(t, "unspecified", attr.Value)
-	case <-time.After(100 * time.Millisecond):
-		assert.Fail(t, "took too long to read an attribute from the list")
-	}
-
-	// Write a partial attribute
-	_, err = wr.Write([]byte("incomplete-file"))
-	assert.NoError(t, err)
-	_, err = wr.Write([]byte("name: "))
-	assert.NoError(t, err)
-	select {
-	case <-wr.ReadAttribute():
-		assert.Fail(t, "There should not be an attribute ready to read")
-	case <-time.After(100 * time.Millisecond):
-	}
-	_, err = wr.Write([]byte("attribute: "))
-	assert.NoError(t, err)
-	select {
-	case <-wr.ReadAttribute():
-		assert.Fail(t, "There should not be an attribute ready to read")
-	case <-time.After(100 * time.Millisecond):
-	}
-	_, err = wr.Write([]byte("value\n"))
-	assert.NoError(t, err)
-	attr := <-wr.ReadAttribute()
-	assert.Equal(t, "incomplete-filename", attr.Filename)
-	assert.Equal(t, "attribute", attr.Attribute)
-	assert.Equal(t, "value", attr.Value)
-}