Align jvmTarget usages across codebase, while editing build.gradle files align them with android version documentation (#164200)

Related to #149836
Find all jvmTarget definitions that do not use JavaVersion.* then update
them.
While editing those files align the usages with
docs/contributing/Android-API-And-Related-Versions.md.

Documentation source that this pr follows
https://github.com/flutter/flutter/pull/164198/files#diff-ee6ec18be8d752e2696c8ccc8bec2f202dfc29a43b3b4f9d8041aa6bc3e852a1


This pr is expected to cause no behavioral changes.
This pr makes logical sense after
https://github.com/flutter/flutter/pull/164198 but can be landed in any
order.

## Pre-launch Checklist

- [x] I read the [Contributor Guide] and followed the process outlined
there for submitting PRs.
- [x] I read the [Tree Hygiene] wiki page, which explains my
responsibilities.
- [x] I read and followed the [Flutter Style Guide], including [Features
we expect every widget to implement].
- [x] I signed the [CLA].
- [x] I listed at least one issue that this PR fixes in the description
above.
- [x] I updated/added relevant documentation (doc comments with `///`).
- [ ] I added new tests to check the change I am making, or this PR is
[test-exempt].
- [x] I followed the [breaking change policy] and added [Data Driven
Fixes] where supported.
- [x] All existing and new tests are passing.

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

@@ -28,7 +28,7 @@ if (flutterVersionName == null) {
 
 android {
     namespace "com.example.spell_check"
-    compileSdk flutter.compileSdkVersion
+    compileSdk = flutter.compileSdkVersion
 
     // Flutter's CI installs the NDK at a non-standard path.
     // This non-standard structure is initially created by
@@ -40,12 +40,12 @@ android {
     }
 
     compileOptions {
-        sourceCompatibility JavaVersion.VERSION_1_8
-        targetCompatibility JavaVersion.VERSION_1_8
+        sourceCompatibility = JavaVersion.VERSION_1_8
+        targetCompatibility = JavaVersion.VERSION_1_8
     }
 
     kotlinOptions {
-        jvmTarget = '1.8'
+        jvmTarget = JavaVersion.VERSION_1_8.toString()
     }
 
     sourceSets {
@@ -57,10 +57,10 @@ android {
         applicationId "com.example.spell_check"
         // You can update the following values to match your application needs.
         // For more information, see: https://docs.flutter.dev/deployment/android#reviewing-the-build-configuration.
-        minSdkVersion flutter.minSdkVersion
-        targetSdkVersion flutter.targetSdkVersion
-        versionCode flutterVersionCode.toInteger()
-        versionName flutterVersionName
+        minSdk = flutter.minSdkVersion
+        targetSdk = flutter.targetSdkVersion
+        versionCode = flutterVersionCode.toInteger()
+        versionName = flutterVersionName
     }
 
     buildTypes {