Calc: Declare dynamic variable bound in lexbind code (bug#40185)

* lisp/calc/calc.el: Declare math-comp-selected as dynamic.
1 job for emacs-27 in 90 minutes
Status Job ID Name Coverage
  Test
failed #5318
test-all

01:30:00

 
Name Stage Failure
failed
test-all Test The script exceeded the maximum execution time set for the job
  GEN      lisp/isearch-tests.log
ELC lisp/jit-lock-tests.elc
GEN lisp/jit-lock-tests.log
ELC lisp/json-tests.elc
GEN lisp/json-tests.log
ELC lisp/jsonrpc-tests.elc
GEN lisp/jsonrpc-tests.log
Pulling docker image gitlab/gitlab-runner-helper:x86_64-d0b76032 ...
ERROR: Job failed: execution took longer than 1h30m0s seconds