[TimePasses] allow -time-passes reporting into a custom stream

[TimePasses] allow -time-passes reporting into a custom stream

TimePassesHandler object (implementation of time-passes for new pass manager)
gains ability to report into a stream customizable per-instance (per pipeline).

Intended use is to specify separate time-passes output stream per each compilation,
setting up TimePasses member of StandardInstrumentation during PassBuilder setup.
That allows to get independent non-overlapping pass-times reports for parallel
independent compilations (in JIT-like setups).

By default it still puts timing reports into the info-output-file stream
(created by CreateInfoOutputFile every time report is requested).

Unit-test added for non-default case, and it also allowed to discover that print() does not work
as declared - it did not reset the timers, leading to yet another report being printed into the default stream.
Fixed print() to actually reset timers according to what was declared in print's comments before.

Reviewed By: philip.pfaffe
Differential Revision: https://reviews.llvm.org/D59366

llvm-svn: 356305