Disable --gdb execopt on darwin.

Darwin now supports only lldb, so we would have to make the behavior
of the --gdb option platform-dependent.  (That is, start lldb if
running on darwin.)

Separate tests would probably be needed for this option, so just
not testing it on darwin for now.
Modify declint2.prediff to remove leading ./ from gdb output of PGI debug data.
Quiet align.chpl errors with Intel and PGI compilers.

The odd behavior on Intel and PGI compilers was due to how a 32-bit temporary was being
inlined:
 - On GCC, the declared size of the temporary (int32_t) was being obeyed, either by being
    written back to a 32-bit memory location, or by being sign-extended inline.
 - On Intel and PGI, the 32-bit result was stored in a 64-bit register and not 32-bit
    sign-extended.

The intent of the test was to demonstrate correct behavior with the first 64-bit integer
not representable as a 32-bit integer.  To avoid compiler dependencies, this constant is
now hard-coded.

The compiler-dependent behavior is captured in a new future with a suggestion for
specifying the behavior that is expected.
Add missing EOL on constOverflow.skipif
Reserving various symbols that appear in darwin
Quiet execflags/bradc/gdbddash/declint2 output on PrgEnv-pgi

The existing prediff script looks for "gdbShouldBreakHere" but in the fast tests, GDB
doesn't print it out at all.

Under PGI, the breakpoint location is printed out with a leading dot-slash.

I solved both problems by modifying the prediff to look for the runtime output
  declint2.chpl:7: error: halt reached - array index out of bounds: (0)
instead.

Since the point of the test is to show that we can run under GDB, if we get as far as
generating error output, we have run the program.  Done.
Merge pull request #722 from benharsh/reserve-darwin

Reserving various symbols that appear on darwin

This patch should fix the darwin compilation errors for compSampler*. 'fls' is the name of a function in darwin, and should become a reserved word in Chapel to avoid compilation errors.

These changes should also fix parallel/sync/diten/userLevelEndCount . The 'wait' function can conflict with darwin functions (wait2/3/4) during C compilation.
Modifications in response to Brad's review.

Use max(int(32)):int(64) + 1 in place of a literal constant.

Removed the "Chapel should ..." phrase.

Added detail to the future, to suggest that runtime overflow checking could be on by
default in debug mode and off by default when optimizations are enabled.
Merge pull request #723 from hildeth/quietGDBdarwin

Quiet gdb execopts test on darwin and PGI platforms.
Merge pull request #721 from hildeth/quietAlignErrors

Quiet align.chpl errors on Intel and PGI.

Changed align.chpl to better demonstrate the original intent.
Added a new future to demonstrate the compiler-dependent behavior.
Suppress constOverflow test when CHPL_TARGET_COMPILER==clang.
Disable static_dynamic for cygwin

This test depends on the file command displaying the link status of the
executable.  However, cygwin's files are in PE format - the file command does
not display many details about this format and I wasn't seeing an option that
would enable it to display correctly.  So, skip it here.
Fix prediff in prgenv-* cases for static_dynamic

The cray programming environments link statically by default, as opposed to
our usual environments which default to dynamic.  The prediff for this test
attempted to take that into account, but was checking against the wrong
environment variable to do so.  Fixing that.
The static flag is not supported on darwin, so skip this test there.
Add declint2.skipif to skip when --fast is tossed.

This test (declint2) is intende to show that GDB will stop when a deliberate
out-of-bounds array access is attempted.  But bounds checking is turned off when
--fast is tossed, so this test does not pertain.
r
Merge pull request #724 from lydia-duncan/fixStaticDynamicTest

Fix static dynamic test [reviewed by David]

This fixes three of the major failing cases for link/sungeun/static_dynamic.

Cygwin: This test depends on the file command displaying the link status of the
executable. However, cygwin's files are in PE format - the file command does
not display many details about this format and I wasn't seeing an option that
would enable it to display correctly. So, skip it here.
PrgEnv-*: The cray programming environments link statically by default, as
opposed to our usual environments which default to dynamic. The prediff for
this test attempted to take that into account, but was checking against the
wrong environment variable to do so. Fixing that.
Darwin: the static flag is not supported on darwin, so running this
test there doesn't really help us.
Updating stories and fixing a typo in REGRESSIONS
Merge pull request #726 from bradcray/triage-sep-blc

Updates from another day of regressions week

New regressions
---------------
* hplx mismatched .bad for gasnet-fast on first run (vass, should be fixed now)


Improvements
------------
* gdbddash tests fixed on darwn (thanks hilde!)

* userLevelEndCount and compSampler* fixed on darwin (thanks Ben!)

* minMod* fixed on memleaks (thanks me!)

* TooManyThreads fixed on valgrind (thanks Lydia!)

* parSafeAdd/Member fixed on gasnet-fast (thanks Ben!)

* mallocOutOfMemory fixed on gasnet-fast (thanks Lydia!)

* fixed nbody_iterator_7 baseline regression (thanks me!)

* performance/multilocale/alloc fixed for cyclic (thanks Greg!)


Misc
----
* no-use-record and record_from_string continue to drain out of testing configs

* noted a new sporadic failure of lulesh on valgrind

* moved c_str_on_remote_string to general gasnet category

* the mysterious swapArrayDiffIndices seemed to quiet up on its own (?!)
  moved it down to sporadic for now, may reconsider before weeks' up

* moved lulesh prgenv-cray OOB errors into more general category
Do not run cobeginRace.chpl when doing memleaks testing.