[flang] Apply implicit typing to names in COMMON that appear in specification expressions

[flang] Apply implicit typing to names in COMMON that appear in specification expressions

Extend semantic analysis of expressions to catch missing cases

Fix statement function semantics, add degree trig intrinsics

Add GetUltimate to rewrite of bare namelist

Address review comments

Original-commit: flang-compiler/f18@52ff319de2e750733660d8e7e938e09159a3c11c
Reviewed-on: https://github.com/flang-compiler/f18/pull/871