[llvm-mca] Add flag -instruction-tables to print the theoretical resource pressure...

[llvm-mca] Add flag -instruction-tables to print the theoretical resource pressure distribution for instructions (PR36874)

The goal of this patch is to address most of PR36874.  To fully fix PR36874 we
need to split the "InstructionInfo" view from the "SummaryView". That would make
easy to check the latency and rthroughput as well.

The patch reuses all the logic from ResourcePressureView to print out the
"instruction tables".

We have an entry for every instruction in the input sequence. Each entry reports
the theoretical resource pressure distribution. Resource pressure is uniformly
distributed across all the processor resource units of a group.

At the moment, the backend pipeline is not configurable, so the only way to fix
this is by creating a different driver that simply sends instruction events to
the resource pressure view.  That means, we don't use the Backend interface.
Instead, it is simpler to just have a different code-path for when flag
-instruction-tables is specified.

Once Clement addresses bug 36663, then we can port the "instruction tables"
logic into a stage of our configurable pipeline.

Updated the BtVer2 test cases (thanks Simon for the help). Now we pass flag
-instruction-tables to each modified test.

Differential Revision: https://reviews.llvm.org/D44839

llvm-svn: 328487