fix some qnx-platform codes

[fxing-qnx]

https://bugs.webkit.org/show_bug.cgi?id=303626

Make the latest version of WebKit working on QNX
https://bugs.webkit.org/show_bug.cgi?id=303626

Reviewed by NOBODY (OOPS!).

- MemoryPressureHandlerUnix.cpp is now included in CMake for QNX
- Stack bounds for each JIT instance was not correctly set, __tls() only return thread infomation for the calling thread rather than a newly spawned thread
- currentExecutablePath() is now implemented for QNX
- stackPointer() is now implemented for QNX
- structureHeapAddressSize is now set to 128M for QNX. QNX does not allowed lazy allocation of memory, mapping 4G will ends up with allocating 4G
- Fix some headers includes
- numberOfProcessorCores() is now implemented for QNX

(computeJSCBytecodeCacheVersion()):
* Source/JavaScriptCore/runtime/JSCBytecodeCacheVersion.cpp:
(static inline void*& stackPointerImpl()):
* Source/JavaScriptCore/runtime/MachineContext.h:
(structureHeapAddressSize):
* Source/JavaScriptCore/runtime/StructureID.h:
(WTF::numberOfProcessorCores()):
* Source/WTF/wtf/NumberOfCores.cpp:
(WTF::StackBounds::currentThreadStackBoundsInternal()):
* Source/WTF/wtf/PlatformHave.h:
* Source/WTF/wtf/StackBounds.cpp:
(WTF::currentExecutablePath()):
* Source/WTF/wtf/glib/FileSystemGlib.cpp:
(WTF::OSAllocator::commit(...)):
* Source/WTF/wtf/posix/OSAllocatorPOSIX.cpp:
* Source/WTF/wtf/PlatformGTK.cmake:

ee9c83b

Misc	iOS, visionOS, tvOS & watchOS	macOS	Linux	Windows
❌ 🧪 style	✅ 🛠 ios	✅ 🛠 mac	✅ 🛠 wpe	🛠 win
	🛠 ios-sim	✅ 🛠 mac-AS-debug	✅ 🧪 wpe-wk2	🧪 win-tests
✅ 🧪 webkitperl	🧪 ios-wk2	✅ 🧪 api-mac	✅ 🧪 api-wpe
	🧪 ios-wk2-wpt	✅ 🧪 api-mac-debug	✅ 🛠 wpe-cairo-libwebrtc
✅ 🛠 🧪 jsc	✅ 🧪 api-ios	✅ 🧪 mac-wk1	✅ 🛠 gtk
✅ 🛠 🧪 jsc-arm64	✅ 🛠 vision	✅ 🧪 mac-wk2	✅ 🧪 gtk-wk2
	✅ 🛠 vision-sim	✅ 🧪 mac-AS-debug-wk2	✅ 🧪 api-gtk
	✅ 🧪 vision-wk2	✅ 🧪 mac-wk2-stress	🛠 playstation
	✅ 🛠 tv	✅ 🧪 mac-intel-wk2	✅ 🛠 jsc-armv7
	✅ 🛠 tv-sim	✅ 🛠 mac-safer-cpp	⏳ 🧪 jsc-armv7-tests
	✅ 🛠 watch
	✅ 🛠 watch-sim

[webkit-early-warning-system]

EWS run on current version of this PR (hash ee9c83b)

Details

Misc	iOS, visionOS, tvOS & watchOS	macOS	Linux	Windows
❌ 🧪 style	✅ 🛠 ios	✅ 🛠 mac	✅ 🛠 wpe	✅ 🛠 win
	✅ 🛠 ios-sim	✅ 🛠 mac-AS-debug	✅ 🧪 wpe-wk2	✅ 🧪 win-tests
✅ 🧪 webkitperl	✅ 🧪 ios-wk2	✅ 🧪 api-mac	✅ 🧪 api-wpe
	✅ 🧪 ios-wk2-wpt	✅ 🧪 api-mac-debug	✅ 🛠 wpe-cairo-libwebrtc
✅ 🛠 🧪 jsc	✅ 🧪 api-ios	✅ 🧪 mac-wk1	✅ 🛠 gtk
✅ 🛠 🧪 jsc-arm64	✅ 🛠 vision	✅ 🧪 mac-wk2	✅ 🧪 gtk-wk2
	✅ 🛠 vision-sim	✅ 🧪 mac-AS-debug-wk2	✅ 🧪 api-gtk
	✅ 🧪 vision-wk2	✅ 🧪 mac-wk2-stress	🛠 playstation
	✅ 🛠 tv	✅ 🧪 mac-intel-wk2	✅ 🛠 jsc-armv7
	✅ 🛠 tv-sim	✅ 🛠 mac-safer-cpp	✅ 🧪 jsc-armv7-tests
	✅ 🛠 watch
	✅ 🛠 watch-sim