attach: fix ptrace signal crash

[meserve-amd]

• Reworks ptrace calls to originate from the same thread per target pid, as required

Motivation

Crashes were observed when extraneous signals were sent to an attached target. Bug introduced in #1653

Prior to #1653, all ptrace operations were handled from a singleton thread in rocattach.cpp. This was changed in favor of re-entrancy support to allow the library to attach to multiple processes simultaneously. This particular detail was lost in the transition.

Technical Details

ptrace session are tracked per thread ID, so all ptrace operations targetting a given PID must originate from the same thread.
This reworks ptrace operations into a new class called PTraceRunner which aims to be as similar to the original ptrace call as possible.

PTraceRunner is a simple single worker thread that handles ptrace operations serially with mutex and atomic mailbox. Each PTraceSession owns a single PTraceRunner that is shared between the main thread and the signal handler thread via shared_ptr.

Aside: ptrace is defined as long ptrace (int op, ...). For consistency's sake, we choose to define it as uint64_t ptrace(__ptrace_operation op, void* addr, void* data). Some changes are made in PTraceSession to enforce the stricter typing.

JIRA ID

Test Plan

Ran parallel-attach test and resized window during test to send extraneous signals (SIGWINCH).
@itrowbri has developed a test which provides a signal mid-attach to ensure this behavior in the future

Test Result

Logging indicated the extraneous signal was handled and sent to the target program.

Submission Checklist

• Look over the contributing guidelines at https://github.com/ROCm/ROCm/blob/develop/CONTRIBUTING.md#pull-requests.

[meserve-amd]

changes requested in #3265
Some refactoring is needed to hide the PTraceRunner class as requested, will update when that is completed

[meserve-amd]

@ROCm/clr-reviewers I've temporarily integrated a commit from #4169 to get PSDB build passing so I can inspect test results. Review is not required and this commit will be removed from this branch before merging.