Fix crash in clang10 muon ART test

Hi,

this MR fixes a crash in the clang10 nightlies, where a fixed-size buffer was used for reading a std::ifstream.

Best, Nico

This merge request affects 1 package:

• MuonSpectrometer/MuonGeoModelTest

This merge request affects 1 file:

• MuonSpectrometer/MuonGeoModelTest/src/PerfUtils.cxx

Adding @rosati ,@nkoehler ,@wleight ,@jojungge as watchers

added MuonSpectrometer master review-pending-level-1 labels

CI Result SUCCESS (hash 3ac80eea)

	Athena	AthSimulation	AthGeneration	AnalysisBase	AthAnalysis
externals
cmake
make
required tests
optional tests

Full details available on this CI monitor view
Athena: number of compilation errors 0, warnings 0
AthSimulation: number of compilation errors 0, warnings 0
AthGeneration: number of compilation errors 0, warnings 0
AnalysisBase: number of compilation errors 0, warnings 0
AthAnalysis: number of compilation errors 0, warnings 0
For experts only: Jenkins output [CI-MERGE-REQUEST-CC7 27079]

added bugfix label

added review-approved label and removed review-pending-level-1 label

merged

mentioned in commit 8a69dfaa

added sweep:ignore label