[query] Ignore name tags for matching binary functions

[arnikola]

What this PR does / why we need it:
Fixes #1520

Special notes for your reviewer:
Fixes an issue in binary functions; previously there was a requirement that series name tags matched to match series from left and right; this drops name tags from binary functions.

NB: this also drops the name tag from appearing in the output series for binary operations with a scalar argument; this is intentional to mirror the same behaviour as Prometheus

Does this PR introduce a user-facing and/or backwards incompatible change?:

Fixes an issue where binary functions would not match series correctly.

Does this PR require updating code package or user-facing documentation?:

NONE

[codecov]

Codecov Report

Merging #1604 into master will decrease coverage by <.1%.
The diff coverage is 100%.

@@           Coverage Diff            @@
##           master   #1604     +/-   ##
========================================
- Coverage    71.9%   71.9%   -0.1%     
========================================
  Files         953     953             
  Lines       78919   78929     +10     
========================================
- Hits        56813   56803     -10     
- Misses      18400   18414     +14     
- Partials     3706    3712      +6

Flag	Coverage Δ
#aggregator	82.3% <ø> (-0.1%)	⬇️
#cluster	85.7% <ø> (ø)	⬆️
#collector	63.7% <ø> (ø)	⬆️
#dbnode	79.9% <ø> (-0.1%)	⬇️
#m3em	73.2% <ø> (ø)	⬆️
#m3ninx	73.9% <ø> (ø)	⬆️
#m3nsch	51.1% <ø> (ø)	⬆️
#metrics	17.6% <ø> (ø)	⬆️
#msg	74.9% <ø> (+0.1%)	⬆️
#query	67.1% <100%> (ø)	⬆️
#x	86.8% <ø> (ø)	⬆️

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[benraskin92]

LGTM