BUG: initialize save_value field to fix uninitialized memory use

[stratakis]

When a HighsSimplexBadBasisChangeRecord is created, save_value is not set until later in applyTabooRowOut/applyTabooVariableIn. Pushing the struct with an uninitialized field copies garbage memory.

Found via Coverity static analysis

[stratakis]

Coverity message:

 17. scipy-1.16.2/subprojects/highs/src/simplex/HEkk.cpp:4022:5: var_decl: Declaring variable "record" without initializer.
18. scipy-1.16.2/subprojects/highs/src/simplex/HEkk.cpp:4028:5: uninit_use_in_call: Using uninitialized value "record". Field "record.save_value" is uninitialized when calling "push_back". [Note: The source code implementation of the function has been overridden by a builtin model.]
  4026|       record.variable_in = variable_in;
  4027|       record.reason = reason;
  4028|->     bad_basis_change_.push_back(record);
  4029|       bad_basis_change_num = bad_basis_change_.size() - 1;
  4030|     } else {

[jajhall]

Well spotted, thanks!