Temp fix for b/77315136: Don't lock or check cache directories in SimpleCache

To be immediately rolled back after submission

Submitting on behalf of cblay.

-------------
Created by MOE: https://github.com/google/moe
MOE_MIGRATED_REVID=191128111

demos/main/src/main/proguard-rules.txt

-# Proguard rules specific to the main demo app.
-
-# Constructor accessed via reflection in PlayerActivity
--dontnote com.google.android.exoplayer2.ext.ima.ImaAdsLoader
--keepclassmembers class com.google.android.exoplayer2.ext.ima.ImaAdsLoader {
-  <init>(android.content.Context, android.net.Uri);
-}

library/core/src/main/java/com/google/android/exoplayer2/upstream/cache/SimpleCache.java

@@ -93,10 +93,6 @@ public final class SimpleCache implements Cache {
    * @param index The CachedContentIndex to be used.
    * @param index The CachedContentIndex to be used.
    */
    */
   /*package*/ SimpleCache(File cacheDir, CacheEvictor evictor, CachedContentIndex index) {
   /*package*/ SimpleCache(File cacheDir, CacheEvictor evictor, CachedContentIndex index) {
-    if (!lockFolder(cacheDir)) {
-      throw new IllegalStateException("Another SimpleCache instance uses the folder: " + cacheDir);
-    }
-
     this.cacheDir = cacheDir;
     this.cacheDir = cacheDir;
     this.evictor = evictor;
     this.evictor = evictor;
     this.index = index;
     this.index = index;

library/core/src/test/java/com/google/android/exoplayer2/upstream/cache/SimpleCacheTest.java

@@ -296,17 +296,17 @@ public class SimpleCacheTest {
     }
     }
   }
   }
 
 
-  @Test
-  public void testMultipleSimpleCacheWithSameCacheDirThrowsException() throws Exception {
-    new SimpleCache(cacheDir, new NoOpCacheEvictor());
-
-    try {
-      new SimpleCache(cacheDir, new NoOpCacheEvictor());
-      assertWithMessage("Exception was expected").fail();
-    } catch (IllegalStateException e) {
-      // Expected. Do nothing.
-    }
-  }
+  //   @Test
+  //   public void testMultipleSimpleCacheWithSameCacheDirThrowsException() throws Exception {
+  //     new SimpleCache(cacheDir, new NoOpCacheEvictor());
+  //
+  //     try {
+  //       new SimpleCache(cacheDir, new NoOpCacheEvictor());
+  //       assertWithMessage("Exception was expected").fail();
+  //     } catch (IllegalStateException e) {
+  //       // Expected. Do nothing.
+  //     }
+  //   }
 
 
   @Test
   @Test
   public void testMultipleSimpleCacheWithSameCacheDirDoesNotThrowsExceptionAfterRelease()
   public void testMultipleSimpleCacheWithSameCacheDirDoesNotThrowsExceptionAfterRelease()