Combine test_b1.py and test_b2.py into test_builtin.py,

port the tests to PyUnit and add many tests for error
cases. This increases code coverage in Python/bltinmodule.c
from 75% to 92%. (From SF patch #662807, with
assert_(not fcmp(x, y)) replaced with assertAlmostEqual(x, y)
where possible)

Lib/test/output/test_builtin

-test_builtin
-4. Built-in functions
-test_b1
-__import__
-abs
-apply
-callable
-chr
-cmp
-coerce
-compile
-complex
-delattr
-dir
-divmod
-eval
-execfile
-filter
-float
-getattr
-hasattr
-hash
-hex
-id
-int
-isinstance
-issubclass
-len
-list
-long
-map
-max
-min
-test_b2
-oct
-open
-ord
-pow
-range
-input and raw_input
-testing
-testing
-reduce
-reload
-repr
-round
-setattr
-str
-tuple
-type
-vars
-xrange
-zip