[CELEBORN-897] Set celeborn.network.memory.allocator.allowCache defau…

…lt to false

### What changes were proposed in this pull request?
As title

### Why are the changes needed?
I tested 1.1T and 3.3T shuffle, as well as 3T TPCDS with thread cache on and off in the shared PooledByteBufAllocator and find no
difference:
| Benchmark    | Cache On | Cache Off|
| -------- | ------- |------- |
|1.1T Shuffle| 3.7min/1.9min   |3.7min/1.9min|
| 3.3T Shuffle| 12min/6.7min  |12min/6.2min|
| 3T TPCDS | 2645s |2644s|

And since the configuration has a big influence to the direct memory usage, see #1716 , it's very necessary to set the default value to false.

### Does this PR introduce _any_ user-facing change?
No.

### How was this patch tested?
Manual test.

Closes #1817 from waitinfuture/897.

Authored-by: zky.zhoukeyong <[email protected]>
Signed-off-by: zky.zhoukeyong <[email protected]>
(cherry picked from commit 57fdbf0)
Signed-off-by: zky.zhoukeyong <[email protected]>

common/src/main/scala/org/apache/celeborn/common/CelebornConf.scala

@@ -1244,7 +1244,7 @@ object CelebornConf extends Logging {
       .version("0.3.1")
       .doc("When false, globally disable thread-local cache in the shared PooledByteBufAllocator.")
       .booleanConf
-      .createWithDefault(true)
+      .createWithDefault(false)
 
   val NETWORK_MEMORY_ALLOCATOR_SHARE: ConfigEntry[Boolean] =
     buildConf("celeborn.network.memory.allocator.share")