src/vs/base/common/diff/diff.ts/LcsDiff/_OriginalRegionIsBoundary
class LcsDiff:	private _OriginalRegionIsBoundary(originalStart: number, originalLength: number): boolean {
		if (this._OriginalIsBoundary(originalStart) || this._OriginalIsBoundary(originalStart - 1)) {
			return true;
		}
		if (originalLength > 0) {
			const originalEnd = originalStart + originalLength;
			if (this._OriginalIsBoundary(originalEnd - 1) || this._OriginalIsBoundary(originalEnd)) {
				return true;
			}
		}
		return false;
	}