[wpiutil] Convert a couple of use cases to std::string

wpiutil/src/main/native/unix/Demangle.cpp

@@ -9,24 +9,22 @@
 #include <cstdio>
 #include <string>
 
-#include "wpi/SmallString.h"
-
 namespace wpi {
 
 std::string Demangle(std::string_view mangledSymbol) {
-  SmallString<128> buf{mangledSymbol};
+  std::string buf{mangledSymbol};
   size_t length;
   int32_t status;
 
   char* symbol = abi::__cxa_demangle(buf.c_str(), nullptr, &length, &status);
   if (status == 0) {
-    std::string rv{symbol};
+    buf = symbol;
     std::free(symbol);
-    return rv;
+    return buf;
   }
 
   // If everything else failed, just return the mangled symbol
-  return std::string{mangledSymbol};
+  return buf;
 }
 
 }  // namespace wpi

wpiutil/src/main/native/unix/StackTrace.cpp

@@ -9,7 +9,6 @@
 #include <string>
 
 #include "wpi/Demangle.h"
-#include "wpi/SmallString.h"
 #include "wpi/StringExtras.h"
 #include "wpi/raw_ostream.h"
 
@@ -20,8 +19,8 @@ std::string GetStackTraceDefault(int offset) {
   void* stackTrace[128];
   int stackSize = backtrace(stackTrace, 128);
   char** mangledSymbols = backtrace_symbols(stackTrace, stackSize);
-  wpi::SmallString<1024> buf;
-  wpi::raw_svector_ostream trace(buf);
+  std::string buf;
+  wpi::raw_string_ostream trace(buf);
 
   for (int i = offset; i < stackSize; i++) {
     // Only print recursive functions once in a row.
@@ -38,7 +37,7 @@ std::string GetStackTraceDefault(int offset) {
 
   std::free(mangledSymbols);
 
-  return std::string{trace.str()};
+  return buf;
 #else
   // backtrace_symbols not supported on android
   return "";