fix: forward stop signal to parent path

[JLHwung]

Q	A
Fixed Issues?	Fixes #14099
Patch: Bug Fix?	Y
Tests Added + Pass?	Yes
License	MIT

In this PR we extract traverse.node into a new routine traverseNode that returns whether the traversal stops early. Because traverse.node is an API, traverse.node now calls traverseNode but returns undefined conditionally. path.visit() now calls traverseNode and set .shouldStop accordingly when the traversal is requested to stop.

For example,

f;g;

has AST

Program - ExpressionStatement (f;) - Identifier (f)
        - ExpressionStatement (g;) - Identifier (g)

when an Identifier visitor requests to stop by calling path.stop(), the signal is not forwarded to ExpressionStatement[] queue visitor because we simply called traverse.node() which lost track of whether the traversal stopped gracefully, so the root traversal continues to g;.

[babel-bot]

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