[trace][intelpt] Support system-wide tracing [21] - Support long numbers in JSON

llvm's JSON parser supports 64 bit integers, but other tools like the
ones written in JS don't support numbers that big, so we need to
represent these possibly big numbers as a string. This diff uses that to
represent addresses and tsc zero. The former is printed in hex for and
the latter in decimal string form. The schema was updated mentioning
that.

Besides that, I fixed some remaining issues and now all test pass. Before I wasn't running all tests because for some reason my computer reverted perf_paranoid to 1.

Differential Revision: https://reviews.llvm.org/D127819