SUSYTools: extra protections for compressed EWK searches

Consolidating various hacks and additions that we've made to SUSYTools for the compressed EWK analysis, for ease of eventual analysis preservation and combinations. Two extra protections are added to account for crashes that came up (justifications in line). We also have four updated cross section files that I've been adding by hand into our local SUSYTools, but unsure if these have been added to PMG and/or elsewhere and this is actually redundant.

Tagging @oabouzei, @ykeisuke, @jmiguens, @szambito, as well as @miholzbo and @jshahini who might know more about the cross section situation.

Thanks!