Generalize swap_inj_on; add simps for Times; add Ex_list_of_length, log_inj; Added missing locale edges for linordered semiring with 1.

proof terms for strip_shyps, based on the version by krauss/schropp with some notable differences: * present type variables are only compared wrt. first component (the atomic type), not the duplicated sort; * extra sorts are grounded towards fixed 'a, potentially with different sorts (the original version with Name.names could cause name clashes with other present variables, too, but this should not be a problem); * deriv_rule_unconditional ensures that proof terms are always maintained independently of the "proofs" flag -- this improves robustness and preserves basic PThm proofs required for extraction attributes, e.g. in theory HOL/Extraction;

simplified/unified fundamental operations on types/terms/proofterms -- prefer Same.operation over "option" variant;

renamed Proofterm.freezeT to Proofterm.legacy_freezeT (cf. 88756a5a92fc);

specification goal: eliminated redundant Thm.legacy_freezeT -- the goal is properly declared and should always produce fixed types in the result; specification result: replaced Thm.legacy_freezeT by Thm.unvarify_global -- the final result appears to be a closed term that is globally exported;

UNDISCH/DISJ_CASESL: eliminated slightly odd Thm.legacy_freezeT -- these rules appear to be applied to thms with fixed types only;

replaced Thm.legacy_freezeT by Thm.unvarify_global -- these facts stem from closed definitions, i.e. there are no term Vars;

renamed Thm.freezeT to Thm.legacy_freezeT -- it is based on Type.legacy_freeze;

minor tuning of Thm.strip_shyps -- no longer pervasive;

simplified primitive Thm.future: more direct theory check, do not hardwire strip_shyps here;