Kernel: Fix sysclib strchr/strrchr, TLS pool leak, FPL counter

- sysclib strchr/strrchr searched for the whole string, not the
  character, so they returned 0 for any nonzero c.
- A thread ending with blocks from more than one TLS pool leaked every
  other block, since the restarted loop's ++iter skipped an entry.
- FPL's nextBlock grew by up to numBlocks per allocation and eventually
  overflowed into a negative block index. Old states with a negative one
  now reset it rather than failing to load.
- sysclib strncpy bounded its copy by the source's valid size only, not
  the destination's.
- sceKernelAllocHeapMemory wrapped for sizes near 4GB, and
  sceKernelGetModuleIdList could write a partial entry past the buffer
  size and dereferenced a missing module.

Co-Authored-By: Claude Opus 5.5 (1M context) <noreply@anthropic.com>

Core/HLE/sceKernelModule.cpp

@@ -3846,8 +3846,12 @@ static u32 sceKernelGetModuleIdList(u32 resultBuffer, u32 resultBufferSize, u32
 	u32 error;
 	for (SceUID moduleId : loadedModules) {
 		PSPModule *module = kernelObjects.Get<PSPModule>(moduleId, error);
+		if (!module) {
+			continue;
+		}
 		if (!module->isFake || liedAboutThisModule(module)) {
-			if (resultBufferOffset < resultBufferSize) {
+			// Only whole entries.
+			if (resultBufferOffset + 4 <= resultBufferSize) {
 				Memory::WriteOrException_U32(module->GetUID(), resultBuffer + resultBufferOffset);
 				resultBufferOffset += 4;
 			}