Add --hot-func-list to llvm-profdata show for sample profiles

Summary:
Add the --hot-func-list feature to llvm-profdata show for sample profiles. This feature prints a list of hot functions whose max sample count are above the 99% threshold, with their numbers of total samples, total samples percentage, max samples, entry samples, and their function names.

Test Plan:

Reviewers: wenlei, hoyFB

Reviewed By: wenlei, hoyFB

Subscribers: hoyFB, wenlei, weihe, llvm-commits

Tags: #llvm

Differential Revision: https://reviews.llvm.org/D82355