[lldb] D66174 `RegularExpression` cleanup

I find as a good cleanup to drop the Compile method. As I do not find TIMTOWTDI
as an advantage and there is already constructor parameter to compile the
regex.

Differential Revision: https://reviews.llvm.org/D66392

llvm-svn: 369352
diff --git a/lldb/source/Plugins/Process/gdb-remote/GDBRemoteCommunication.cpp b/lldb/source/Plugins/Process/gdb-remote/GDBRemoteCommunication.cpp
index b447203..bb283b7 100644
--- a/lldb/source/Plugins/Process/gdb-remote/GDBRemoteCommunication.cpp
+++ b/lldb/source/Plugins/Process/gdb-remote/GDBRemoteCommunication.cpp
@@ -332,11 +332,12 @@
             std::string regex_str = "^";
             regex_str += echo_packet;
             regex_str += "$";
-            response_regex.Compile(regex_str);
+            response_regex = RegularExpression(regex_str);
           } else {
             echo_packet_len =
                 ::snprintf(echo_packet, sizeof(echo_packet), "qC");
-            response_regex.Compile(llvm::StringRef("^QC[0-9A-Fa-f]+$"));
+            response_regex =
+                RegularExpression(llvm::StringRef("^QC[0-9A-Fa-f]+$"));
           }
 
           PacketResult echo_packet_result =