twister: Fix gTest harness

The gTest harness asssumed that the lines end with the test name, but
some gTest implementations include the test duration in the line. Update
both the tests and regex to allow this and also avoid capturing
characters into the `test_name` that cannot be valid test name chars.

Fixes #72318

Signed-off-by: Yuval Peress <peress@google.com>