Add kotlinOptions jvmTarget to templates (flutter#147326)

Adds jvmTarget to gradle templates. 

Fixes flutter#147185.

Interestingly, we already had this in many of our examples/tests, see search results here https://github.com/search?q=repo%3Aflutter%2Fflutter%20jvmTarget&type=code.

Author: gmackall

dev/integration_tests/abstract_method_smoke_test/android/app/build.gradle

@@ -4,8 +4,8 @@
 
 plugins {
     id "com.android.application"
-    id "dev.flutter.flutter-gradle-plugin"
     id "kotlin-android"
+    id "dev.flutter.flutter-gradle-plugin"
 }
 
 def localProperties = new Properties()

dev/integration_tests/android_embedding_v2_smoke_test/android/app/build.gradle

@@ -4,8 +4,8 @@
 
 plugins {
     id "com.android.application"
-    id "dev.flutter.flutter-gradle-plugin"
     id "kotlin-android"
+    id "dev.flutter.flutter-gradle-plugin"
 }
 
 def localProperties = new Properties()

dev/integration_tests/android_semantics_testing/android/app/build.gradle

@@ -4,8 +4,8 @@
 
 plugins {
     id "com.android.application"
-    id "dev.flutter.flutter-gradle-plugin"
     id "kotlin-android"
+    id "dev.flutter.flutter-gradle-plugin"
 }
 
 def localProperties = new Properties()
@@ -25,6 +25,10 @@ android {
         targetCompatibility JavaVersion.VERSION_1_8
     }
 
+    kotlinOptions {
+        jvmTarget = JavaVersion.VERSION_1_8
+    }
+
     defaultConfig {
         minSdkVersion flutter.minSdkVersion
         targetSdkVersion flutter.targetSdkVersion

dev/integration_tests/channels/android/app/build.gradle

@@ -36,6 +36,10 @@ android {
         targetCompatibility JavaVersion.VERSION_1_8
     }
 
+    kotlinOptions {
+        jvmTarget = JavaVersion.VERSION_1_8
+    }
+
     defaultConfig {
         // TODO: Specify your own unique Application ID (https://developer.android.com/studio/build/application-id.html).
         applicationId "com.example.channels"

dev/integration_tests/non_nullable/android/app/build.gradle

@@ -4,8 +4,8 @@
 
 plugins {
     id "com.android.application"
-    id "dev.flutter.flutter-gradle-plugin"
     id "kotlin-android"
+    id "dev.flutter.flutter-gradle-plugin"
 }
 
 def localProperties = new Properties()

dev/integration_tests/release_smoke_test/android/app/build.gradle

@@ -4,8 +4,8 @@
 
 plugins {
     id "com.android.application"
-    id "dev.flutter.flutter-gradle-plugin"
     id "kotlin-android"
+    id "dev.flutter.flutter-gradle-plugin"
 }
 
 def localProperties = new Properties()
@@ -35,6 +35,10 @@ android {
         targetCompatibility JavaVersion.VERSION_1_8
     }
 
+    kotlinOptions {
+        jvmTarget = JavaVersion.VERSION_1_8
+    }
+
     defaultConfig {
         // TODO: Specify your own unique Application ID (https://developer.android.com/studio/build/application-id.html).
         applicationId "com.example.release_smoke_test"

dev/integration_tests/spell_check/android/app/build.gradle

@@ -4,8 +4,8 @@
 
 plugins {
     id "com.android.application"
-    id "dev.flutter.flutter-gradle-plugin"
     id "kotlin-android"
+    id "dev.flutter.flutter-gradle-plugin"
 }
 
 def localProperties = new Properties()

dev/integration_tests/ui/android/app/build.gradle

@@ -17,6 +17,10 @@ android {
         targetCompatibility JavaVersion.VERSION_1_8
     }
 
+    kotlinOptions {
+        jvmTarget = JavaVersion.VERSION_1_8
+    }
+
     defaultConfig {
         minSdkVersion flutter.minSdkVersion
         targetSdkVersion flutter.targetSdkVersion

packages/flutter_tools/templates/app_shared/android-java.tmpl/app/build.gradle.tmpl

@@ -15,6 +15,10 @@ android {
         targetCompatibility = JavaVersion.VERSION_1_8
     }
 
+    kotlinOptions {
+        jvmTarget = JavaVersion.VERSION_1_8
+    }
+
     defaultConfig {
         // TODO: Specify your own unique Application ID (https://developer.android.com/studio/build/application-id.html).
         applicationId = "{{androidIdentifier}}"

packages/flutter_tools/templates/app_shared/android-kotlin.tmpl/app/build.gradle.tmpl

@@ -15,6 +15,10 @@ android {
         targetCompatibility = JavaVersion.VERSION_1_8
     }
 
+    kotlinOptions {
+        jvmTarget = JavaVersion.VERSION_1_8
+    }
+
     defaultConfig {
         // TODO: Specify your own unique Application ID (https://developer.android.com/studio/build/application-id.html).
         applicationId = "{{androidIdentifier}}"

packages/flutter_tools/templates/plugin/android-kotlin.tmpl/build.gradle.tmpl

@@ -37,7 +37,7 @@ android {
     }
 
     kotlinOptions {
-        jvmTarget = "1.8"
+        jvmTarget = JavaVersion.VERSION_1_8
     }
 
     sourceSets {