Added test cases to FoundationTestCase to exercise lookup of objc data types and

to evaluate expressions.  Marked with @expectedFailure decorators for the time
being.

Enhanced the lldbtest.TestBase.expect() API to allow an additional keyword arg
named "error".  If the client passes "error=True", it signifies that an error
while running the command is expected.  The golden input is then compared
against the return object's error output.

llvm-svn: 114228