Eliminate a Clang -fsanitize=undefined error for memmove.
Eliminate a Clang -fsanitize=undefined error for memmove.

The memmove function has its memory arguments marked as __nonnull. Stop
calling memmove of the size is zero anyway.

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