[clang-tidy] Make the cert/uppercase-literal-suffix-integer fully hermetic.

[clang-tidy] Make the cert/uppercase-literal-suffix-integer fully hermetic.

after the test-reorg commit (89a1d03e2b379e325daa5249411e414bbd995b5e), the
cert/uppercase test starts to fail in our internal environment -- it accesses
a header file from "../readability", which is not friendly to a hermetic test environment.

This change makes the test fully hermetic, and does some cleanup on the
uppercase header (I think it is better to move it the share
Inputs/Header directory, and rename it)

Differential Revision: https://reviews.llvm.org/D128511