mtest: fix test output issues (in console)

This change set aims to fix various "issues" seen with the current
implementation. The changes can be summarized with the following list:

* Replace emojis and spinners with multiline status displaying the name
  and running time of each currently running test.
* The test output (especially in verbose mode or when multiple failing
  tests' output gets printed out) can get confusing. Try to make the
  output easier to read and grasp. Most notable change here is the
  addition of the test number to the beginning of each printed line.
* Print exit details (i.e. exit code) of the test in verbose mode.
* Try to make the verbose "live" output from tests to match the look and
  feel of otherwise produced (verbose) test output.

mesonbuild/mlog.py

@@ -158,6 +158,9 @@ def __str__(self) -> str:
 def bold(text: str, quoted: bool = False) -> AnsiDecorator:
     return AnsiDecorator(text, "\033[1m", quoted=quoted)
 
+def italic(text: str, quoted: bool = False) -> AnsiDecorator:
+    return AnsiDecorator(text, "\033[3m", quoted=quoted)
+
 def plain(text: str) -> AnsiDecorator:
     return AnsiDecorator(text, "")