fuzz: Update FuzzedDataProvider.h from upstream (LLVM)

Upstream revision: https://github.com/llvm/llvm-project/blob/6d0488f75bb2f37bcfe93fc8f59f6e78c9a0c939/compiler-rt/include/fuzzer/FuzzedDataProvider.h

Changes:
* [compiler-rt] FuzzedDataProvider: add ConsumeData and method.
* [compiler-rt] Fix a typo in a comment in FuzzedDataProvider.h.
* [compiler-rt] Add ConsumeRandomLengthString() version without arguments.
* [compiler-rt] Refactor FuzzedDataProvider for better readability.
* [compiler-rt] FuzzedDataProvider: make linter happy.
* [compiler-rt] Mark FDP non-template methods inline to avoid ODR violations.

Author: practicalswift