It's possible for this logic to fail if the build system runs this
script in parallel. One instance could create the directory in between
another instance's checking of its existence and attempt at creation.

Instead, always try to create it and ignore any FileExistsErrors.

rdar://160120161

Removes the U that comes before the guards passed into the framework
fixup script.

When gathering the headers to fix up and place in LLDB.framework, we
were previously globbing the header files from a location in the build
directory. This commit changes this to glob from the source directory
instead, as we were globbing from the build directory without ensuring
that the necessary files were actually in that location before globbing.

There's 2 bugs that this commit fixes:
1. Calculate the correct file path for the output file by appending the
basename of the input header instead of appending the entire input
header's path to the framework path.
2. In the script, create the framework's header directory if it does not
exist.

The script used to fix up LLDB's header for use in the macOS framework
contained 2 bugs that this commit addreses:

1. The output contents were appended to the output file multiple times
instead of only being written once.
2. The script was not considering LLDB includes that were *not* from the
SB API.

This commit addresses and fixes both of these bugs and updates the
corresponding test to match.

…ers" (#143941)

Reland the script that converts lldb headers to RPC headers. The RPC
test was failing due to the incorrect input filepath being used.

Original commit message:
This commit replaces the shell script that fixes up includes for the
LLDB framework with a Python script. This script will also be used when
fixing up includes for the LLDBRPC.framework.

Reverts llvm/llvm-project#142051

This commit replaces the shell script that fixes up includes for the
LLDB framework with a Python script. This script will also be used when
fixing up includes for the LLDBRPC.framework.