Simplify the CMake-generated lit.py invocation.

Now it's down to what I use myself, plus the --xunit-xml-output flag.
I also threw out a fair number of options we weren't using.

Swift SVN r31646

test/Unit/lit.cfg

@@ -21,15 +21,7 @@ if swift_obj_root is not None:
     config.test_source_root = config.test_exec_root
 
 # testFormat: The test format to use to interpret tests.
-llvm_build_mode = getattr(config, 'llvm_build_mode', "Debug")
-config.test_format = lit.formats.GoogleTest(llvm_build_mode, 'Tests')
-
-# Propagate the temp directory. Windows requires this because it uses \Windows\
-# if none of these are present.
-if 'TMP' in os.environ:
-    config.environment['TMP'] = os.environ['TMP']
-if 'TEMP' in os.environ:
-    config.environment['TEMP'] = os.environ['TEMP']
+config.test_format = lit.formats.GoogleTest(config.build_mode, 'Tests')
 
 ###
 
@@ -79,11 +71,3 @@ if config.test_exec_root is None:
     lit_config.note('using out-of-tree build at %r' % swift_obj_root)
     lit_config.load_config(config, site_cfg)
     raise SystemExit
-
-# If necessary, point the dynamic loader at libLLVM.so.
-if config.enable_shared:
-    shlibpath = config.environment.get(config.shlibpath_var,'')
-    if shlibpath:
-        shlibpath = os.pathsep + shlibpath
-    shlibpath = config.shlibdir + shlibpath
-    config.environment[config.shlibpath_var] = shlibpath

test/Unit/lit.site.cfg.in

@@ -4,23 +4,9 @@ config.llvm_src_root = "@LLVM_SOURCE_DIR@"
 config.llvm_obj_root = "@LLVM_BINARY_DIR@"
 config.llvm_tools_dir = "@LLVM_TOOLS_DIR@"
 config.llvm_libs_dir = "@LLVM_LIBS_DIR@"
-config.llvm_build_mode = "@LLVM_BUILD_MODE@"
+config.build_mode = lit_config.params.get('build_mode', "@LLVM_BUILD_MODE@")
 config.swift_obj_root = "@SWIFT_BINARY_DIR@"
-config.enable_shared = @ENABLE_SHARED@
-config.shlibdir = "@SHLIBDIR@"
-config.shlibpath_var = "@SHLIBPATH_VAR@"
 config.target_triple = "@TARGET_TRIPLE@"
 
-# Support substitution of the tools_dir, libs_dirs, and build_mode with user
-# parameters. This is used when we can't determine the tool dir at
-# configuration time.
-try:
-    config.llvm_tools_dir = config.llvm_tools_dir % lit_config.params
-    config.llvm_libs_dir = config.llvm_libs_dir % lit_config.params
-    config.llvm_build_mode = config.llvm_build_mode % lit_config.params
-except KeyError,e:
-    key, = e.args
-    lit_config.fatal("unable to find %r parameter, use '--param=%s=VALUE'" % (key,key))
-
 # Let the main config do the real work.
 lit_config.load_config(config, "@SWIFT_SOURCE_DIR@/test/Unit/lit.cfg")

test/lit.site.cfg.in

@@ -16,16 +16,6 @@ config.targets_to_build = "@TARGETS_TO_BUILD@"
 config.variant_triple = "@VARIANT_TRIPLE@"
 config.variant_sdk = "@VARIANT_SDK@"
 
-# Support substitution of the tools and libs dirs with user parameters. This is
-# used when we can't determine the tool dir at configuration time.
-try:
-    config.llvm_tools_dir = config.llvm_tools_dir % lit_config.params
-    config.llvm_libs_dir = config.llvm_libs_dir % lit_config.params
-except KeyError:
-    e = sys.exc_info()[1]
-    key, = e.args
-    lit_config.fatal("unable to find %r parameter, use '--param=%s=VALUE'" % (key,key))
-
 if "@SWIFT_ASAN_BUILD@" == "TRUE":
     config.available_features.add("asan")
 else:

validation-test/lit.site.cfg.in

@@ -15,16 +15,6 @@ config.targets_to_build = "@TARGETS_TO_BUILD@"
 config.variant_triple = "@VARIANT_TRIPLE@"
 config.variant_sdk = "@VARIANT_SDK@"
 
-# Support substitution of the tools and libs dirs with user parameters. This is
-# used when we can't determine the tool dir at configuration time.
-try:
-    config.llvm_tools_dir = config.llvm_tools_dir % lit_config.params
-    config.llvm_libs_dir = config.llvm_libs_dir % lit_config.params
-except KeyError:
-    e = sys.exc_info()[1]
-    key, = e.args
-    lit_config.fatal("unable to find %r parameter, use '--param=%s=VALUE'" % (key,key))
-
 if "@SWIFT_ASAN_BUILD@" == "TRUE":
     config.available_features.add("asan")