Tests: Prevent array reallocations during ts_stack_print_dot_graph

When debugging a test with 'script/test -D', the DOT-graph generation
code was sometimes causing reallocations that were not captured by the
allocation tracker, because we explicitly disable allocation-tracking
for that method in order to reduce noise when debugging memory leaks.

By growing the relevant array *prior* to turning off allocation
tracking, we can ensure that it is not reallocated within that function,
avoiding false positive memory leak errors.

Fixes #302

cli/src/tests/helpers/allocations.rs

@@ -98,7 +98,9 @@ extern "C" fn ts_record_free(ptr: *mut c_void) {
 }
 
 #[no_mangle]
-extern "C" fn ts_record_allocations_toggle() {
+extern "C" fn ts_toggle_allocation_recording(enabled: bool) -> bool {
     let mut recorder = RECORDER.lock();
-    recorder.enabled = !recorder.enabled;
+    let was_enabled = recorder.enabled;
+    recorder.enabled = enabled;
+    was_enabled
 }

lib/src/alloc.h

@@ -15,7 +15,7 @@ void *ts_record_malloc(size_t);
 void *ts_record_calloc(size_t, size_t);
 void *ts_record_realloc(void *, size_t);
 void ts_record_free(void *);
-bool ts_record_allocations_toggle(bool);
+bool ts_toggle_allocation_recording(bool);
 
 static inline void *ts_malloc(size_t size) {
   return ts_record_malloc(size);
@@ -33,10 +33,6 @@ static inline void ts_free(void *buffer) {
   ts_record_free(buffer);
 }
 
-static inline bool ts_toggle_allocation_recording(bool value) {
-  return ts_record_allocations_toggle(value);
-}
-
 #else
 
 #include <stdlib.h>

lib/src/stack.c

@@ -712,9 +712,9 @@ void ts_stack_clear(Stack *self) {
 }
 
 bool ts_stack_print_dot_graph(Stack *self, const TSLanguage *language, FILE *f) {
+  array_reserve(&self->iterators, 32);
   bool was_recording_allocations = ts_toggle_allocation_recording(false);
-  if (!f)
-    f = stderr;
+  if (!f) f = stderr;
 
   fprintf(f, "digraph stack {\n");
   fprintf(f, "rankdir=\"RL\";\n");