Replace a single dash with a double dash for options that have more
than a single letter.
llvm-bolt-wrapper.py has special treatment for output options such as
"-o" and "-w" causing issues when a single dash is used, e.g. for
"-write-dwp". The wrapper can be fixed as well, but using a double dash
has other advantages as well.
Reviewed By: rafauler
Differential Revision: https://reviews.llvm.org/D127538
Summary:
The majority of tests in LLVM projects are using - instead of _ in the name,
i.e. `check-something.test` is preferred over `check_something.test`.
It makes sense for us to adopt the same naming scheme for our future tests and
to rename existing ones.
(cherry picked from FBD32185879)
