Fix two loop issues

rfe13107: Fix for-in-sequence path missing declaration

bug22148: Fix loop type checking failure

Change-Id: I0e738e2d0ecda474ffcde4617255b9a19c57bb1c
Set up code for a fix to variable decl checks

checkpoint for bug16933: Fix variable declarations in general
when the initial value does not match the type declared for
the variable.  This is not done yet, and for now can be turned
on by setting excl::*do-locally-declare* to non-nil.

Change-Id: I157b7df73b2cbd4b4292fdaf2f07229ffd1e0c67
Turn on the loop high-safety type warning fix

bug16933:
bug20368:
bug21721: Fix warnings in loop code when compiling under high safety.

Change-Id: Iea970cc93a60969bba91745cdf54ff64947a9a61