Add a new test_options.tags attribute to customize test execution

The `test_options.tags` attribute provides additional metadata to
customize test execution by downstream test runners. The tags have no
special meaning to Soong.

Bug: 240928948
Test: manually add `test_options.tags` attribute and run:
    $ refreshmod && \
      cat out/target/product/generic/module-info.json |\
      grep <tags>
Change-Id: I35267f6608e48c6184e56530ef128d93b2f97522

android/module_test.go

@@ -912,7 +912,7 @@ func TestSortedUniqueNamedPaths(t *testing.T) {
 	}
 }
 
-func TestProcessCommonTestOptions(t *testing.T) {
+func TestSetAndroidMkEntriesWithTestOptions(t *testing.T) {
 	tests := []struct {
 		name        string
 		testOptions CommonTestOptions
@@ -939,6 +939,31 @@ func TestProcessCommonTestOptions(t *testing.T) {
 			},
 			expected: map[string][]string{},
 		},
+		{
+			name: "empty tag",
+			testOptions: CommonTestOptions{
+				Tags: []string{},
+			},
+			expected: map[string][]string{},
+		},
+		{
+			name: "single tag",
+			testOptions: CommonTestOptions{
+				Tags: []string{"tag1"},
+			},
+			expected: map[string][]string{
+				"LOCAL_TEST_OPTIONS_TAGS": []string{"tag1"},
+			},
+		},
+		{
+			name: "multiple tag",
+			testOptions: CommonTestOptions{
+				Tags: []string{"tag1", "tag2", "tag3"},
+			},
+			expected: map[string][]string{
+				"LOCAL_TEST_OPTIONS_TAGS": []string{"tag1", "tag2", "tag3"},
+			},
+		},
 	}
 	for _, tt := range tests {
 		t.Run(tt.name, func(t *testing.T) {