recordLoopEntry method
Records that loop is being entered, before it pushes anything.
Implementation
void recordLoopEntry(SAstNode loop) {
loopEntryDepths[loop] = LoopStackDepths(
nodes: loopNodeStack.length,
environments: loopEnvironmentStack.length,
initialized: loopInitializedStack.length,
awaitFor: awaitForNodeStack.length,
);
}