[ci] use a suppression file with valgrind checks

[jameslamb]

Summary

This project occasionally runs valgrind to check for memory management issues.

Those checks are currently run only on the code paths touched by the R package's tests. It generates a few false positives, and those are currently prevented from failing the relevant CI job via text-parsing in a shell script.

A valgrind suppression file should be used for that purpose instead.

Motivation

• allows for finer-grained control over which errors from valgrind the project regards as noteworthy
• makes the configuration portable outside of using R to run valgrind

Description

To fix this, remove this stuff:

LightGBM/.ci/test_r_package_valgrind.sh

Lines 48 to 69 in 522f0f0

	# one error caused by a false positive between valgrind and openmp is allowed
	# ==2063== 352 bytes in 1 blocks are possibly lost in loss record 153 of 2,709
	# ==2063== at 0x483DD99: calloc (in /usr/lib/x86_64-linux-gnu/valgrind/vgpreload_memcheck-amd64-linux.so)
	# ==2063== by 0x40149CA: allocate_dtv (dl-tls.c:286)
	# ==2063== by 0x40149CA: _dl_allocate_tls (dl-tls.c:532)
	# ==2063== by 0x5702322: allocate_stack (allocatestack.c:622)
	# ==2063== by 0x5702322: pthread_create@@GLIBC_2.2.5 (pthread_create.c:660)
	# ==2063== by 0x56D0DDA: ??? (in /usr/lib/x86_64-linux-gnu/libgomp.so.1.0.0)
	# ==2063== by 0x56C88E0: GOMP_parallel (in /usr/lib/x86_64-linux-gnu/libgomp.so.1.0.0)
	# ==2063== by 0x1544D29C: LGBM_DatasetCreateFromCSC (c_api.cpp:1286)
	# ==2063== by 0x1546F980: LGBM_DatasetCreateFromCSC_R (lightgbm_R.cpp:91)
	# ==2063== by 0x4941E2F: R_doDotCall (dotcode.c:634)
	# ==2063== by 0x494CCC6: do_dotcall (dotcode.c:1281)
	# ==2063== by 0x499FB01: bcEval (eval.c:7078)
	# ==2063== by 0x498B67F: Rf_eval (eval.c:727)
	# ==2063== by 0x498E414: R_execClosure (eval.c:1895)
	bytes_possibly_lost=$(
	cat ${VALGRIND_LOGS_FILE} \
	| grep -E "possibly lost\: .*" \
	| sed 's/^.*possibly lost\: \(.*\) bytes.*$/\1/' \
	| tr -d ","
	)

And instead check in a file, .ci/valgrind.supp, into the repo which suppresses those specific errors.

To test, run the valgrind checks in a container, following https://github.com/microsoft/LightGBM/tree/master/R-package#valgrind.

References

• https://wiki.wxwidgets.org/Valgrind_Suppression_File_Howto
• https://valgrind.org/