Cleanup branch unit test

[nkoukpaizan]

Description

Looks like something went wrong in #417 . The accessor method in BranchTests is not called from runBranchTests, and it somehow contains Jacobian tests.

Proposed changes

• Remove accessor method. It was replaced with parameterSetters.
• [Minor] Remove ad-hoc tol = 1e-12 The default for isEqual should work.

Checklist

• All tests pass.
• Code compiles cleanly with flags -Wall -Wpedantic -Wconversion -Wextra.
• [N/A] The new code follows GridKit™ style guidelines.
• [N/A] There are unit tests for the new code.
• [N/A] The new code is documented.
• The feature branch is rebased with respect to the target branch.
• [N/A] I have updated CHANGELOG.md to reflect the changes in this PR. If this is a minor PR that is part of a larger fix already included in the file, state so.

Further comments

[lukelowry]

Appears I forgot to remove the old function after I made parameterSetters. Thank you. Looks good