MIPS: Reland of `Fix bad RegisterConfiguration usage in InstructionSequence unit tests`

src/compiler/instruction.cc

Index: src/compiler/instruction.cc
diff --git a/src/compiler/instruction.cc b/src/compiler/instruction.cc
index e53414bdb1ea5ce0b9aa30c28845ed055458d5b0..c4560b6e76774faa6b81ad0b092ba375f7f46cd1 100644
--- a/src/compiler/instruction.cc
+++ b/src/compiler/instruction.cc
@@ -12,7 +12,8 @@ namespace v8 {
 namespace internal {
 namespace compiler {
 
-const auto GetRegConfig = RegisterConfiguration::Turbofan;
+const RegisterConfiguration* (*GetRegConfig)() =
+    RegisterConfiguration::Turbofan;
 
 FlagsCondition CommuteFlagsCondition(FlagsCondition condition) {
   switch (condition) {
@@ -985,6 +986,21 @@ void InstructionSequence::PrintBlock(int block_id) const {
   PrintBlock(GetRegConfig(), block_id);
 }
 
+const RegisterConfiguration*
+    InstructionSequence::registerConfigurationForTesting_ = nullptr;
+
+const RegisterConfiguration*
+InstructionSequence::RegisterConfigurationForTesting() {
+  DCHECK(registerConfigurationForTesting_ != nullptr);
+  return registerConfigurationForTesting_;
+}
+
+void InstructionSequence::SetRegisterConfigurationForTesting(
+    const RegisterConfiguration* regConfig) {
+  registerConfigurationForTesting_ = regConfig;
+  GetRegConfig = InstructionSequence::RegisterConfigurationForTesting;
+}
+
 FrameStateDescriptor::FrameStateDescriptor(
     Zone* zone, FrameStateType type, BailoutId bailout_id,
     OutputFrameStateCombine state_combine, size_t parameters_count,