Add support for ./dotest.py --channel and --log-success

Summary:
New dotest options that allow arbitrary log channels and
categories to be enabled.  Also enables logging for locally run
debug servers.
    
Log messages are separated into separate files per test case.
(this makes it possible to log in dosep runs)
    
These new log files are stored side-by-side with trace files in the
session directory.
    
These files are deleted by default if the test run is successful.
    
If --log-success is specified, even successful logs are retained.
    
--log-success is useful for creating reference log files.
    
Test Plan:
add '--channel "lldb all" --channel "gdb-remote packets" --log-success'
to your dotest options

Tested on OSX and Linux
    
Differential Revision: http://reviews.llvm.org/D9594

llvm-svn: 236956
diff --git a/lldb/test/lldbtest_config.py b/lldb/test/lldbtest_config.py
new file mode 100644
index 0000000..96703d7
--- /dev/null
+++ b/lldb/test/lldbtest_config.py
@@ -0,0 +1,17 @@
+"""
+                     The LLVM Compiler Infrastructure
+
+ This file is distributed under the University of Illinois Open Source
+ License. See LICENSE.TXT for details.
+
+Configuration options for lldbtest.py set by dotest.py during initialization
+"""
+
+# array of strings
+# each string has the name of an lldb channel followed by
+# zero or more categories in that channel
+# ex. "gdb-remote packets"
+channels = []
+
+# leave logs/traces even for successful test runs
+log_success = False