capitalize SCEV to match the current naming convention
add NestLoops to remove some uses of IVS
don't store a pointer to the loop in IVS
check that clang-format exists
capitalize SCEV to match the current naming convention
More test case cleanup (Linux and Mac):
- remove expectedFailure decorator from resolved rdar 12566646 and 10887661
- remove expectedFailure from TestBitfields testcase not actually affected by bug
- skip the (non-deterministic) TestStopHookMechanism.py to avoid a noisy suite on Linux
Add the 'target-cpu' and 'target-features' attributes to functions.

The back-end will use these values to reconfigure code generation for different
features.
Improve test harness for the buildbots
- Add a "parsable" mode to dotest.py that outputs test results in exactly the same format as clang's lit tests
- Improve dosep script to output list of failing tests (output should look like clang test failure summaries)
- Cleanup lldb/test/Makefile to remove needless parameters and environment variables
- Switch makefile tests to use parsable-mode output; should make the buildbot results parsable
- Switch makefile tests to use dosep to log catch crashing tests (instead of halting the test suite)