fix non-monotonicity in StartVarDurationVarIntervalVariable
fix non-monotonicity in StartVarDurationVarIntervalVariable

or-tools/or-tools,google/or-tools,or-tools/or-tools,legrosbuffle/or-tools,google/or-tools,google/or-tools,or-tools/or-tools,or-tools/or-tools,ThatRfernand/or-tools,legrosbuffle/or-tools,ThatRfernand/or-tools,or-tools/or-tools,ThatRfernand/or-tools,legrosbuffle/or-tools,or-tools/or-tools,legrosbuffle/or-tools,google/or-tools,google/or-tools,ThatRfernand/or-tools,ThatRfernand/or-tools,legrosbuffle/or-tools,google/or-tools