Simulator trace will display content of target floating point registers.
Content of FP registers is displayed in hexadecimal form which is
followed with float or/and double interpretation.
Also, with this implementation will be displayed contents of general
purpose registers (GPRs). Hexadecimal form is followed with signed
and unsigned integer interpretation (32-bit or/and 64-bit).

TEST=
BUG=

Review-Url: https://codereview.chromium.org/2603083002
Cr-Commit-Position: refs/heads/master@{#42911}