Adding EXTRACT builtin.

Change-Id: I6de20f336ecdfa3acd8d3a9166cff4a062baaacc
Reviewed-on: http://gerrit.ent.cloudera.com:8080/2247
Reviewed-by: Victor Bittorf <victor.bittorf@cloudera.com>
Tested-by: jenkins
IMPALA-934: Refresh cached UDF library when creating a new function

This change adds the ability to refresh a local cache entry, causing
the old cache entry to be dropped and the library to be reloaded from
HDFS. This is used in ResolveSymbolLookup(), which is called by the
frontend when creating a new a function, and in ImpalaServer when
receiving a "create function" heartbeat. This change also makes sure
the FE calls into the backend for jars, so jars get refreshed as well.

Change-Id: I5fd61c1bc2e04838449335d5a68b61af8b101b01
Reviewed-on: http://gerrit.ent.cloudera.com:8080/2286
Reviewed-by: Skye Wanderman-Milne <skye@cloudera.com>
Tested-by: jenkins
CDH-18416: Don't inline ReadWriteUtil::ReadZLong()

For wide Avro tables, ReadZLong() would get inlined many times into a
single function body, causing LLVM to crash. Not inlining doesn't seem
to have a performance impact on narrow tables, and helps with wide
tables.

This change also adds tests over wide (i.e. many-column) tables. The
test tables are produced by specifying shell commands to generate test
tables in functional_schema_template.sql, which are executed in
generate-schema-statements.py. In the SQL templates, sections starting
with a ` are treated as shell commands. The output of the shell
command is then used as the section text. This is only a starting
point; it isn't currently implemented for all sections, and may have
to be tweaked if we use this mechanism for all tables.

Change-Id: Ife0d857d19b21534167a34c8bc06bc70bef34910
Reviewed-on: http://gerrit.ent.cloudera.com:8080/2206
Reviewed-by: Skye Wanderman-Milne <skye@cloudera.com>
Tested-by: Skye Wanderman-Milne <skye@cloudera.com>