(SQLite3) Disabled call to sqlite3_load_extension

This function is also not always present in the sqlite3 library
(Binary Analysis) Fixed use-def bug in symbolic semantics

* Current instruction was sometimes added as a definer when it
  shouldn't have been added.
(Binary Analysis) semantics test output for API2 is more similar to the old API1 output
(Binary Analysis) DO NOT MERGE TO MASTER

Temporary changes to make SymbolicSemantics use-def in API2 to behave
similarly to the API1 version.  The API1 version does not make
careful distinction between use-def computed on values and use-def
computed on abstract locations.

This change should not be merged into the public release branch
because it introduces incorrect behavior.