[Kotlin] Fix CI by changing compiler to Java 11

With the changes introduced on google#6729, google#6671, google#6658 it seems that using java
compiler version 8 is no longer possible. We are adjusting our CI build for
Kotlin to use Java 11 as compiler, while still emiting 1.8 bytecode.

The Kotlin CI action is also being breakdown into two: Mac & Linux.
Kotlin mac will test ios & mac builds while Linux will test js and JVM.
This change will improve build times for Kotlin on CI, which is currently
taking long times.

.github/workflows/build.yml

@@ -120,18 +120,36 @@ jobs:
       working-directory: tests
       run: bash JavaTest.sh
 
-  build-kotlin:
-    name: Build Kotlin
+  build-kotlin-macos:
+    name: Build Kotlin MacOS
     runs-on: macos-latest
     steps:
     - name: Checkout
-      uses: actions/checkout@v1
+      uses: actions/checkout@v2
+    - uses: actions/setup-java@v2
+      with:
+        distribution: 'adopt-hotspot'
+        java-version: '11'
+    - name: Build
+      working-directory: kotlin
+      run: ./gradlew clean iosX64Test macosX64Test jsTest jsBrowserTest
+
+  build-kotlin-linux:
+    name: Build Kotlin Linux
+    runs-on: ubuntu-latest
+    steps:
+    - name: Checkout
+      uses: actions/checkout@v2
+    - uses: actions/setup-java@v2
+      with:
+        distribution: 'adopt-hotspot'
+        java-version: '11'
     - name: Build
       working-directory: kotlin
-      run: ./gradlew clean build allTests
+      run: ./gradlew jvmMainClasses jvmTest
     - name: Run Benchmark
       working-directory: kotlin
-      run: ./gradlew benchmark
+      run: ./gradlew jvmBenchmark
     - name: Generate Benchmark Report
       working-directory: kotlin
       run: |