Reset yul string repository.

libsolidity/interface/CompilerStack.cpp

@@ -47,6 +47,8 @@
 
 #include <libevmasm/Exceptions.h>
 
+#include <libyul/YulString.h>
+
 #include <libdevcore/SwarmHash.h>
 #include <libdevcore/JSON.h>
 
@@ -104,6 +106,7 @@ void CompilerStack::reset(bool _keepSources)
 		m_stackState = Empty;
 		m_sources.clear();
 	}
+	yul::YulStringRepository::instance().reset();
 	m_libraries.clear();
 	m_evmVersion = EVMVersion();
 	m_optimize = false;