When printing setting variables using the python SBDebugger API if the type is of OptionValueFileSpec
it defaults to null as the value even if it has a value. This patch fixes that.

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Signed-off-by: Ebuka Ezike <yerimyah1@gmail.com>
Co-authored-by: Jonas Devlieghere <jonas@devlieghere.com>

When I added the MD5 checksum I was on the fence between storing it in
FileSpec or creating a new SupportFile abstraction. The latter was
deemed overkill for just the MD5 hashes, but support for inline sources
in the DWARF 5 line table tipped the scales. This patch moves the MD5
checksum into the new SupportFile class.

This patch replaces uses of StringRef::{starts,ends}with with
StringRef::{starts,ends}_with for consistency with
std::{string,string_view}::{starts,ends}_with in C++20.

I'm planning to deprecate and eventually remove
StringRef::{starts,ends}with.

Store a Checksum in FileSpec. Its purpose is to store the MD5 hash that
was added to the DWARF 5 line table.

This increases the size of a FileSpec from 24 to 40 bytes. The
alternative is to introduce a new SupportFile abstraction for a FileSpec
+ Checksum but that would require a corresponding SupportFileList class.
During review we decided that wasn't worth it, but that's something we
can revisit in the future.

In preparation for removing the `#include "llvm/ADT/StringExtras.h"`
from the header to source file of `llvm/Support/Error.h`, first add in
all the missing includes that were previously included transitively
through this header.

This is fixing all files missed in b0abd4893fa1, 39d8e6e22cd1, and
a11efd49266f.

Differential Revision: https://reviews.llvm.org/D154775

This patch introduces FileSpec::GetComponents, a method that splits a
FileSpec's path into its individual components. For example, given
/foo/bar/baz, you'll get back a vector of strings {"foo", "bar", baz"}.

The motivation here is to reduce the use of
`FileSpec::RemoveLastPathComponent`. Mutating a FileSpec is expensive,
so providing a way of doing this without mutation is useful.

Differential Revision: https://reviews.llvm.org/D151399

As far as I can tell, this just computes the filename of the FileSpec,
which is already conveniently stored in m_filename. We can use
FileSpec::GetFilename() instead.

Differential Revision: https://reviews.llvm.org/D149663

These don't really need to be in ConstStrings. It's nice that comparing
ConstStrings is fast (just a pointer comparison) but the cost of
creating the ConstString usually already includes the cost of doing a
StringRef comparison anyway, so this is just extra work and extra memory
consumption for basically no benefit.

Differential Revision: https://reviews.llvm.org/D149300

I also ran `git clang-format` to get the headers in the right order for
the new location, which has changed the order of other headers in two
files.