There’s something giddily pure about Gurinder Chadha’s “Blinded by the Light,” a coming-of-age story about a young Pakistani Muslim boy growing up in late eighties Luton. With the country experiencing the economic and social turmoil of Thatcherism, Javed (Viveik Kalra) and his family must endure not only financial hardship but the hostility and bigotry of the local National Front. Javed finds…