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/Plugins/Process/gdb-remote/GDBRemoteCommunication.cpp b/lldb/source/Plugins/Process/gdb-remote/GDBRemoteCommunication.cpp
index 2c0a5e0..de7d524 100644
--- a/lldb/source/Plugins/Process/gdb-remote/GDBRemoteCommunication.cpp
+++ b/lldb/source/Plugins/Process/gdb-remote/GDBRemoteCommunication.cpp
@@ -404,11 +404,11 @@
             std::string regex_str = "^";
             regex_str += echo_packet;
             regex_str += "$";
-            response_regex.Compile(regex_str.c_str());
+            response_regex.Compile(regex_str);
           } else {
             echo_packet_len =
                 ::snprintf(echo_packet, sizeof(echo_packet), "qC");
-            response_regex.Compile("^QC[0-9A-Fa-f]+$");
+            response_regex.Compile(llvm::StringRef("^QC[0-9A-Fa-f]+$"));
           }
 
           PacketResult echo_packet_result =
@@ -422,8 +422,7 @@
                   echo_response, timeout_usec, false);
               if (echo_packet_result == PacketResult::Success) {
                 ++successful_responses;
-                if (response_regex.Execute(
-                        echo_response.GetStringRef().c_str())) {
+                if (response_regex.Execute(echo_response.GetStringRef())) {
                   sync_success = true;
                   break;
                 } else if (successful_responses == 1) {