Core: always free memory on exit, always report leaks

Instead of allowing leaks when parsing arguments, always cleanup before
calling exit(). This impacts -a (animation player), --help & --version
arguments, as well as scripts executed via --python which meant tests
that ran scripts could leak memory without raising an error as intended.

Avoid having suppress warnings & rationalize in code-comments when
leaking memory is/isn't acceptable, any leaks from the animation-player
are now reported as well.

This change exposed leaks: !140182, !140116.

Ref !140098

intern/guardedalloc/MEM_guardedalloc.h

@@ -269,12 +269,6 @@ extern void (*MEM_name_ptr_set)(void *vmemh, const char *str) ATTR_NONNULL();
  */
 void MEM_init_memleak_detection(void);
 
-/**
- * Use this if we want to call #exit during argument parsing for example,
- * without having to free all data.
- */
-void MEM_use_memleak_detection(bool enabled);
-
 /**
  * When this has been called and memory leaks have been detected, the process will have an exit
  * code that indicates failure. This can be used for when checking for memory leaks with automated

intern/guardedalloc/intern/leak_detector.cc

@@ -24,15 +24,11 @@ char free_after_leak_detection_message[] =
 namespace {
 
 bool fail_on_memleak = false;
-bool ignore_memleak = false;
 
 class MemLeakPrinter {
  public:
   ~MemLeakPrinter()
   {
-    if (ignore_memleak) {
-      return;
-    }
     leak_detector_has_run = true;
     const uint leaked_blocks = MEM_get_memory_blocks_in_use();
     if (leaked_blocks == 0) {
@@ -83,11 +79,6 @@ void MEM_init_memleak_detection()
   static MemLeakPrinter printer;
 }
 
-void MEM_use_memleak_detection(bool enabled)
-{
-  ignore_memleak = !enabled;
-}
-
 void MEM_enable_fail_on_memleak()
 {
   fail_on_memleak = true;