(Reuters) - London shares gained on Wednesday as an enormous U.S. stimulus package and evidence of moves by companies to deal with the financial effects of the coronavirus crisis offset the impact on markets of a surge in cases domestically. The blue-chip FTSE 100 , down 30% in the past month, on Tuesday saw its best day since the swings of the financial crisis of 2008. It had recovered another 1.4% by 0811 GMT, as oil & gas companies, drugmakers and insurers rose. U.S. senators and the Trump..