optimizes functional tests

[gitoleg]

This PR removes expect from most of the test cases and adds a couple of primitives to match against the output of any command.

Examples

• Match bap bir and find the main function according to the pattern:

 match $file bir "" {
     "sub .*main" {pass "$test $file"}
     default {fail "$test $file"}
 }

• Match bap ouptut for --version option:

match_output "bap" "--version" {
    "error" {fail $test}
    "1" {pass $test}
}

• Check that all strings can be found in the output:

find_all $file bir $lines $test

Fixes #1136