[strong] Refactor ObjectStrength into a replacement for strong boolean args

src/mips/lithium-mips.h

Index: src/mips/lithium-mips.h
diff --git a/src/mips/lithium-mips.h b/src/mips/lithium-mips.h
index 92e3426df5ccb9cb1b4dc34513e260c9389cdbd4..809e6e0410a1407db624905cdb1dcdbe92ff3476 100644
--- a/src/mips/lithium-mips.h
+++ b/src/mips/lithium-mips.h
@@ -1154,7 +1154,7 @@ class LCmpT final : public LTemplateInstruction<1, 3, 0> {
   DECLARE_CONCRETE_INSTRUCTION(CmpT, "cmp-t")
   DECLARE_HYDROGEN_ACCESSOR(CompareGeneric)
 
-  LanguageMode language_mode() { return hydrogen()->language_mode(); }
+  Strength strength() { return hydrogen()->strength(); }
 
   Token::Value op() const { return hydrogen()->token(); }
 };
@@ -1512,7 +1512,7 @@ class LArithmeticT final : public LTemplateInstruction<1, 3, 0> {
 
   DECLARE_HYDROGEN_ACCESSOR(BinaryOperation)
 
-  LanguageMode language_mode() { return hydrogen()->language_mode(); }
+  Strength strength() { return hydrogen()->strength(); }
 
  private:
   Token::Value op_;