Bump Robolectric to 4.7.3

shell/platform/android/test/README.md

@@ -1,6 +1,6 @@
 # Unit testing Java code
 
-All Java code in the engine should now be able to be tested with Robolectric 4.6.1
+All Java code in the engine should now be able to be tested with Robolectric 4.7.3
 and JUnit 4. The test suite has been added after the bulk of the Java code was
 first written, so most of these classes do not have existing tests. Ideally code
 after this point should be tested, either with unit tests here or with

shell/platform/android/test/io/flutter/plugin/platform/SingleViewPresentationTest.java

@@ -1,5 +1,8 @@
 package io.flutter.plugin.platform;
 
+import static android.os.Build.VERSION_CODES.JELLY_BEAN_MR1;
+import static android.os.Build.VERSION_CODES.P;
+import static android.os.Build.VERSION_CODES.R;
 import static junit.framework.Assert.assertEquals;
 import static org.mockito.Mockito.mock;
 import static org.mockito.Mockito.spy;
@@ -18,9 +21,10 @@
 
 @Config(manifest = Config.NONE)
 @RunWith(RobolectricTestRunner.class)
-@TargetApi(28)
+@TargetApi(P)
 public class SingleViewPresentationTest {
   @Test
+  @Config(minSdk = JELLY_BEAN_MR1, maxSdk = R)
   public void returnsOuterContextInputMethodManager() {
     // There's a bug in Android Q caused by the IMM being instanced per display.
     // https://github.com/flutter/flutter/issues/38375. We need the context returned by
@@ -51,6 +55,7 @@ public void returnsOuterContextInputMethodManager() {
   }
 
   @Test
+  @Config(minSdk = JELLY_BEAN_MR1, maxSdk = R)
   public void returnsOuterContextInputMethodManager_createDisplayContext() {
     // The IMM should also persist across display contexts created from the base context.
 

shell/platform/android/test_runner/build.gradle

@@ -44,7 +44,7 @@ android {
     testImplementation "androidx.test:core:1.4.0"
     testImplementation "com.google.android.play:core:1.8.0"
     testImplementation "com.ibm.icu:icu4j:69.1"
-    testImplementation "org.robolectric:robolectric:4.6.1"
+    testImplementation "org.robolectric:robolectric:4.7.3"
     testImplementation "junit:junit:4.13"
 
     def mockitoVersion = "4.1.0"

shell/platform/android/test_runner/src/main/resources/robolectric.properties

@@ -1 +1 @@
-sdk=30
+sdk=31