Remove BIGINT type redirection from PrecomputedHashGenerator

BIGINT.getLong is called with multiple Block types
i.e. not only LongArrayBlock but also DictionaryBlock, RunLengthEncodedBlock.
This sometime confuses JIT to do virtual call in the
PrecomputedHashGenerator even if the PrecomputedHashGenerator is
only called with LongArrayBlock and the call to PrecomputedHashGenerator is inlined.

core/trino-main/src/main/java/io/trino/operator/PrecomputedHashGenerator.java

@@ -14,7 +14,7 @@
 package io.trino.operator;
 
 import io.trino.spi.Page;
-import io.trino.spi.type.BigintType;
+import io.trino.spi.block.Block;
 
 import static com.google.common.base.MoreObjects.toStringHelper;
 
@@ -31,7 +31,8 @@ public PrecomputedHashGenerator(int hashChannel)
     @Override
     public long hashPosition(int position, Page page)
     {
-        return BigintType.BIGINT.getLong(page.getBlock(hashChannel), position);
+        Block hashBlock = page.getBlock(hashChannel);
+        return hashBlock.getLong(position, 0);
     }
 
     @Override