Rename lldb registers to contain lldb_ prefix.

LLDB supports many different register numbering schemes, and these
are typically prefixed with an indicator that lets the user know
what numbering scheme is used.  The gcc numbering scheme is
prefixed with gcc, and there are similar ones for dwarf, gdb,
and gcc_dwarf.

LLDB also contains its own internal numbering scheme, but the enum
for LLDB's numbering scheme was prefixed differently.  This patch
changes the names of these enums to use the same naming scheme for
the enum values as the rest of the register kinds by removing gpr_
and fpu_ prefixes, and instead using lldb_ prefixes for all enum
values.

Differential Revision: http://reviews.llvm.org/D6351
Reviewed by: Greg Clayton

git-svn-id: https://llvm.org/svn/llvm-project/lldb/trunk@222495 91177308-0d34-0410-b5e6-96231b3b80d8
Change CommandObjectTargetModulesLoad so that the filename argument
is treated as a string instead of a FileSpec.

OptionValueFileSpec::SetValueFromCString() passes the c string to
FileSpec::SetFile(str, true /* resolve */) - and with Zachary's
changes to FileSpec we're using llvm::sys::fs::make_absolute() to
do that "resolve" action now, where we used to use realpath().

One important difference between llvm::sys::fs::make_absolute and
realpath is that when they're handed a filename (no directory),
realpath prepends the current working directory *and if the file exists*,
returns that full path.  If that file doesn't exist, the caller 
uses the basename only.

llvm::sys::fs::make_absolute prepends the current working directory
regardless of whether it exists or not. 

I considered having FileSpec::SetFile save the initial pathname,
call FileSpec::Resolve, and then check to see if the Resolve return
path exists - and if not, go back to the original one.

But instead I just went with changing 'target modules load' to treat its 
filename argument as a string instead of a FileSpec.  This brings it
in line with how 'target modules list' works.

<rdar://problem/18955416> 


git-svn-id: https://llvm.org/svn/llvm-project/lldb/trunk@222498 91177308-0d34-0410-b5e6-96231b3b80d8
Rework parallel test process count logic

The default value for opt.thread_count was multiprocessing.cpu_count(),
which meant the LLDB_TEST_THREADS environment variable was never used.
It's not easy to pass the -t option to the test run when invoking it
from e.g. 'ninja check-lldb', so having the environment variable as an
option is useful.

Change the logic so that the thread count is set by the first one of:

  1. The -t option to test/dosep.py
  2. The LLDB_TEST_THREADS environment variable
  3. The machine's CPU count from multiprocessing.cpu_count()


git-svn-id: https://llvm.org/svn/llvm-project/lldb/trunk@222501 91177308-0d34-0410-b5e6-96231b3b80d8