sanitizers: Add suppression for unsigned-integer-overflow in libstdc++ basic_string.tcc

Author: jonasschnelli

test/sanitizer_suppressions/ubsan

@@ -6,6 +6,7 @@
 # contains files in which we expect unsigned integer overflows to occur. The
 # list is used to suppress -fsanitize=integer warnings when running our CI UBSan
 # job.
+unsigned-integer-overflow:*/include/c++/*/bits/basic_string.tcc
 unsigned-integer-overflow:arith_uint256.h
 unsigned-integer-overflow:basic_string.h
 unsigned-integer-overflow:bench/bench.h