HIVE-21563: Improve Table#getEmptyTable performance by disabling registerAllFunctionsOnce

[wangyum]

What changes were proposed in this pull request?

Improve Table#getEmptyTable performance by disabling registerAllFunctionsOnce.

Why are the changes needed?

Table#getEmptyTable do not need registerAllFunctionsOnce . The stack trace:

  at org.apache.hadoop.hive.ql.exec.Registry.registerGenericUDF(Registry.java:177)
  at org.apache.hadoop.hive.ql.exec.Registry.registerGenericUDF(Registry.java:170)
  at org.apache.hadoop.hive.ql.exec.FunctionRegistry.<clinit>(FunctionRegistry.java:209)
  at org.apache.hadoop.hive.ql.metadata.Hive.reloadFunctions(Hive.java:247)
  at org.apache.hadoop.hive.ql.metadata.Hive.registerAllFunctionsOnce(Hive.java:231)
  at org.apache.hadoop.hive.ql.metadata.Hive.<init>(Hive.java:388)
  at org.apache.hadoop.hive.ql.metadata.Hive.create(Hive.java:332)
  at org.apache.hadoop.hive.ql.metadata.Hive.getInternal(Hive.java:312)
  at org.apache.hadoop.hive.ql.metadata.Hive.get(Hive.java:288)
  at org.apache.hadoop.hive.ql.session.SessionState.setAuthorizerV2Config(SessionState.java:913)
  at org.apache.hadoop.hive.ql.session.SessionState.setupAuth(SessionState.java:877)
  at org.apache.hadoop.hive.ql.session.SessionState.getAuthenticator(SessionState.java:1479)
  at org.apache.hadoop.hive.ql.session.SessionState.getUserFromAuthenticator(SessionState.java:1150)
  at org.apache.hadoop.hive.ql.metadata.Table.getEmptyTable(Table.java:180)

Does this PR introduce any user-facing change?

No.

How was this patch tested?

Existing test.

[wangyum]

cc @sunchao

[sunchao]

Thanks @wangyum ! LGTM pending on CI.