Replace StringPiece with std::string_view.

This replaces the last few StringPiece uses and removes
the stringpiece.h.

Test: m test-art-host-gtest
Test: testrunner.py --host --optimizing
Bug: 123750182
Change-Id: I1bb5d05df47319b6ca386db01e14ce048ae54daf
diff --git a/compiler/jit/jit_compiler.cc b/compiler/jit/jit_compiler.cc
index 4d7ae9b..2c20b32 100644
--- a/compiler/jit/jit_compiler.cc
+++ b/compiler/jit/jit_compiler.cc
@@ -22,7 +22,7 @@
 #include "arch/instruction_set_features.h"
 #include "art_method-inl.h"
 #include "base/logging.h"  // For VLOG
-#include "base/stringpiece.h"
+#include "base/string_view_cpp20.h"
 #include "base/systrace.h"
 #include "base/time_utils.h"
 #include "base/timing_logger.h"
@@ -71,19 +71,19 @@
     DCHECK_EQ(instruction_set, kRuntimeISA);
   }
   std::unique_ptr<const InstructionSetFeatures> instruction_set_features;
-  for (const StringPiece option : runtime->GetCompilerOptions()) {
+  for (const std::string& option : runtime->GetCompilerOptions()) {
     VLOG(compiler) << "JIT compiler option " << option;
     std::string error_msg;
-    if (option.starts_with("--instruction-set-variant=")) {
-      StringPiece str = option.substr(strlen("--instruction-set-variant=")).data();
+    if (StartsWith(option, "--instruction-set-variant=")) {
+      const char* str = option.c_str() + strlen("--instruction-set-variant=");
       VLOG(compiler) << "JIT instruction set variant " << str;
       instruction_set_features = InstructionSetFeatures::FromVariant(
-          instruction_set, str.as_string(), &error_msg);
+          instruction_set, str, &error_msg);
       if (instruction_set_features == nullptr) {
         LOG(WARNING) << "Error parsing " << option << " message=" << error_msg;
       }
-    } else if (option.starts_with("--instruction-set-features=")) {
-      StringPiece str = option.substr(strlen("--instruction-set-features=")).data();
+    } else if (StartsWith(option, "--instruction-set-features=")) {
+      const char* str = option.c_str() + strlen("--instruction-set-features=");
       VLOG(compiler) << "JIT instruction set features " << str;
       if (instruction_set_features == nullptr) {
         instruction_set_features = InstructionSetFeatures::FromVariant(
@@ -93,7 +93,7 @@
         }
       }
       instruction_set_features =
-          instruction_set_features->AddFeaturesFromString(str.as_string(), &error_msg);
+          instruction_set_features->AddFeaturesFromString(str, &error_msg);
       if (instruction_set_features == nullptr) {
         LOG(WARNING) << "Error parsing " << option << " message=" << error_msg;
       }