Stop running shrinking gcs & simplify GC logic.

Shrinking GCs dump the JITted code, which leads to redundant recompilations, lowers performance, and makes profiling JS more difficult.
They may still happen if the runtime is at risk of OOM.

source/ps/GameSetup/GameSetup.cpp

@@ -536,7 +536,7 @@ bool Init(const CmdLineArgs& args, int flags)
 	// Using a global object for the context is a workaround until Simulation and AI use
 	// their own threads and also their own contexts.
 	const int contextSize = 384 * 1024 * 1024;
-	const int heapGrowthBytesGCTrigger = 20 * 1024 * 1024;
+	const int heapGrowthBytesGCTrigger = 12 * 1024 * 1024;
 	g_ScriptContext = ScriptContext::CreateContext(contextSize, heapGrowthBytesGCTrigger);
 
 	// On the first Init (INIT_MODS), check for command-line arguments