Revert the Android specific max heap size GCConfig

Summary:
Changelog:
[Category][Internal]

This diff reverts the [Androids-specific heap size overrides](github.com/facebook/react-native/commit/63d20d3b1ef35cb4398d63d62f631f7f5d2935c7#diff-4c59ddca85e294a90a0e1bd15ed323ff4e130911d9642680dde44aacbcd7d32c) after
[Hermes has changed its default max heap size to 3GiB](https://github.com/facebook/hermes/commit/5f2b47d0be6281fd2605d24efc0b43af42b4033d).
You can read about more context there.

Reviewed By: yungsters

Differential Revision: D30726067

fbshipit-source-id: 1bcc93fdf4da817f3b3d60bd09c6a5a64166eb7e

ReactAndroid/src/main/java/com/facebook/hermes/reactexecutor/HermesExecutorFactory.java

@@ -17,7 +17,7 @@ public class HermesExecutorFactory implements JavaScriptExecutorFactory {
   private final RuntimeConfig mConfig;
 
   public HermesExecutorFactory() {
-    this(new RuntimeConfig(1024));
+    this(null);
   }
 
   public HermesExecutorFactory(RuntimeConfig config) {

ReactAndroid/src/main/java/com/facebook/hermes/reactexecutor/RuntimeConfig.java

@@ -10,10 +10,4 @@ package com.facebook.hermes.reactexecutor;
 /** Holds runtime configuration for a Hermes VM instance (master or snapshot). */
 public final class RuntimeConfig {
   public long heapSizeMB;
-
-  RuntimeConfig() {}
-
-  RuntimeConfig(long heapSizeMB) {
-    this.heapSizeMB = heapSizeMB;
-  }
 }