WASHINGTON — A unanimous Supreme Court on Tuesday sided with the government in a legal clash over the nation’s insider trading laws, a victory for prosecutors seeking to curb corruption on Wall Street. The justices ruled that sharing corporate secrets with friends or relatives is illegal even if the insider providing the tip doesn’t receive anything of value in return. The ruling upheld the conviction of Bassam Yacoub Salman, an Illinois man convicted of making investments based on inside information he received from a member of his extended family.