No need for mutable, Remove flaky tests

Author: msooseth

libyul/optimiser/VarNameCleaner.cpp

@@ -104,9 +104,7 @@ YulName VarNameCleaner::findCleanName(YulName const& _name) const
 
 	// Use a per-base-name counter to avoid O(n²) probing when many
 	// variables share the same stripped base name.
-	size_t& nextSuffix = m_nextSuffix.at(newName);
-	if (nextSuffix == 0)
-		nextSuffix = 1;
+	size_t nextSuffix = util::valueOrDefault(m_nextSuffix, newName, static_cast<size_t>(1));
 	for (; nextSuffix < std::numeric_limits<size_t>::max(); ++nextSuffix)
 	{
 		YulName newNameSuffixed = YulName{newName.str() + "_" + std::to_string(nextSuffix)};

libyul/optimiser/VarNameCleaner.h

@@ -90,7 +90,7 @@ class VarNameCleaner: public ASTModifier
 	std::set<YulName> m_usedNames;
 
 	/// Next suffix to try per stripped base name, avoids O(n²) probing.
-	mutable std::map<YulName, size_t> m_nextSuffix;
+	std::map<YulName, size_t> m_nextSuffix;
 
 	/// Maps old to new names.
 	std::map<YulName, YulName> m_translatedNames;