[query] Fix Graphite compiler eagerly parsing identifier as function call and not considering pattern

[robskillington]

What this PR does / why we need it:

Fixes the case where Graphite compiler eagerly parses an identifier that matches a function name (i.e. max) but is actually just an identifier.

Added unit test that covers this case.

Special notes for your reviewer:

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

NONE

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

NONE

[codecov]

Codecov Report

Merging #3656 (e77ed4f) into master (9f82e9a) will increase coverage by 0.0%.
The diff coverage is n/a.

@@          Coverage Diff           @@
##           master   #3656   +/-   ##
======================================
  Coverage    56.1%   56.1%           
======================================
  Files         551     551           
  Lines       61876   61876           
======================================
+ Hits        34755   34767   +12     
+ Misses      23994   23979   -15     
- Partials     3127    3130    +3     

Flag	Coverage Δ
aggregator	57.1% <ø> (ø)
cluster	∅ <ø> (∅)
collector	58.4% <ø> (ø)
dbnode	60.7% <ø> (+<0.1%)	⬆️
m3em	46.4% <ø> (ø)
metrics	19.8% <ø> (ø)
msg	74.2% <ø> (-0.2%)	⬇️

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