Remove Android code from shared Java file (#465)

Author: borrrden

common/main/java/com/couchbase/lite/internal/exec/ConcurrentExecutor.java

@@ -15,8 +15,6 @@
 //
 package com.couchbase.lite.internal.exec;
 
-import android.os.Build;
-
 import androidx.annotation.GuardedBy;
 import androidx.annotation.NonNull;
 import androidx.annotation.Nullable;
@@ -143,11 +141,7 @@ void finishTask() {
     private void executeTask(@NonNull InstrumentedTask newTask) {
         try {
             executor.execute(() -> {
-                if (Build.VERSION.SDK_INT >= Build.VERSION_CODES.BAKLAVA) {
-                    currentThread = Thread.currentThread().threadId();
-                } else {
-                    currentThread = Thread.currentThread().getId();
-                }
+                currentThread = Thread.currentThread().getId();
                 newTask.run();
                 currentThread = -1;
             });

common/main/java/com/couchbase/lite/internal/exec/SerialExecutor.java

@@ -15,8 +15,6 @@
 //
 package com.couchbase.lite.internal.exec;
 
-import android.os.Build;
-
 import androidx.annotation.GuardedBy;
 import androidx.annotation.NonNull;
 import androidx.annotation.Nullable;
@@ -166,11 +164,7 @@ private void executeTask(@Nullable InstrumentedTask prevTask) {
         if (nextTask == null) { return; }
 
         try { executor.execute(() -> {
-            if (Build.VERSION.SDK_INT >= Build.VERSION_CODES.BAKLAVA) {
-                currentThread = Thread.currentThread().threadId();
-            } else {
-                currentThread = Thread.currentThread().getId();
-            }
+            currentThread = Thread.currentThread().getId();
             nextTask.run();
             currentThread = -1;
         }); }

common/test/java/com/couchbase/lite/BaseDbTest.kt

@@ -171,6 +171,7 @@ abstract class BaseDbTest : BaseTest() {
         testTg = getUniqueName("db_test_tag")
 
         testExec = object : CloseableExecutor {
+            var currentThread: Long = -1
             val executor: ThreadPoolExecutor = ThreadPoolExecutor(
                 1, 1,
                 30, TimeUnit.SECONDS,
@@ -196,15 +197,21 @@ abstract class BaseDbTest : BaseTest() {
             override fun execute(task: Runnable) {
                 Report.log("task enqueued: %s", task)
                 executor.execute {
+                    currentThread = Thread.currentThread().id
                     Report.log("Test task started: %s", task)
                     try {
                         task.run()
                     } finally {
+                        currentThread = -1
                         Report.log("Test task finished: %s", task)
                     }
                 }
             }
 
+            override fun isInsideExecutor(): Boolean {
+                return Thread.currentThread().id == currentThread;
+            }
+
             override fun getPending(): Int {
                 return executor.queue.size
             }