orbit: replace regex assertions with string assertions
orbit: replace regex assertions with string assertions

This commit may also make some minor modifications to the tests
to further improve the style (e.g. removing unecessary escapes,
using `assert_equal` instead of `assert_match`, and removing
unecessary regex modifiers).

I have done some additional work to ensure that this formula
continues to work as expected. I have not necessarily tested
every aspect of this particular formula, but I have tested one
where I made similar changes and feel confident that this will
not cause major breakage. In some cases, I did test this particular
formula. This is a generic commit message which has not been
tailored to this particular formula, so it is very possible that I
did actually test this formula.

lemzwerg/homebrew-core,cblecker/homebrew-core,mbcoguno/homebrew-core,lemzwerg/homebrew-core,chrisfinazzo/homebrew-core,mbcoguno/homebrew-core,sjackman/homebrew-core,filcab/homebrew-core,stgraber/homebrew-core,nandub/homebrew-core,Moisan/homebrew-core,filcab/homebrew-core,mfikes/homebrew-core,spaam/homebrew-core,Homebrew/homebrew-core,spaam/homebrew-core,JCount/homebrew-core,mbcoguno/homebrew-core,zyedidia/homebrew-core,stgraber/homebrew-core,makigumo/homebrew-core,Linuxbrew/homebrew-core,mfikes/homebrew-core,Moisan/homebrew-core,dsXLII/homebrew-core,uyjulian/homebrew-core,chrisfinazzo/homebrew-core,nandub/homebrew-core,uyjulian/homebrew-core,Homebrew/homebrew-core,zyedidia/homebrew-core,nbari/homebrew-core,adam-moss/homebrew-core,Linuxbrew/homebrew-core,makigumo/homebrew-core,sjackman/homebrew-core,adam-moss/homebrew-core,cblecker/homebrew-core,dsXLII/homebrew-core,nbari/homebrew-core,JCount/homebrew-core