add missing math.trunc for js backend (#6950)
add missing math.trunc for js backend (#6950)


russpowers/Nim,dom96/Nim,dom96/Nim,russpowers/Nim,dom96/Nim,dom96/Nim,russpowers/Nim,russpowers/Nim,russpowers/Nim,dom96/Nim,dom96/Nim,russpowers/Nim,dom96/Nim,russpowers/Nim