Make lldb::Regex use StringRef.

This updates getters and setters to use StringRef instead of
const char *.  I tested the build on Linux, Windows, and OSX
and saw no build or test failures.  I cannot test any BSD
or Android variants, however I expect the required changes
to be minimal or non-existant.

llvm-svn: 282079
diff --git a/lldb/source/Symbol/ObjectFile.cpp b/lldb/source/Symbol/ObjectFile.cpp
index fd233cc..4616208 100644
--- a/lldb/source/Symbol/ObjectFile.cpp
+++ b/lldb/source/Symbol/ObjectFile.cpp
@@ -574,9 +574,10 @@
                                             FileSpec &archive_file,
                                             ConstString &archive_object,
                                             bool must_exist) {
-  RegularExpression g_object_regex("(.*)\\(([^\\)]+)\\)$");
+  RegularExpression g_object_regex(llvm::StringRef("(.*)\\(([^\\)]+)\\)$"));
   RegularExpression::Match regex_match(2);
-  if (g_object_regex.Execute(path_with_object, &regex_match)) {
+  if (g_object_regex.Execute(llvm::StringRef::withNullAsEmpty(path_with_object),
+                             &regex_match)) {
     std::string path;
     std::string obj;
     if (regex_match.GetMatchAtIndex(path_with_object, 1, path) &&