[flang] add C1120, C1122 and placehokders for C1006, C1121, and C1123

add a new test for C1120
Fix new test's CHECKs
More contraints hacking

Original-commit: flang-compiler/f18@197e5fd75083d0ca9773b2f75df54fba0ada9dc8
Reviewed-on: https://github.com/flang-compiler/f18/pull/196
Tree-same-pre-rewrite: false