Comment out forced GC.gc() calls in test_getindex_algs (#740)

Co-authored-by: Claude Fable 5 <noreply@anthropic.com>

Author: KristofferC

test/sparsematrix_constructors_indexing.jl

@@ -834,7 +834,9 @@ end
             times = Float64[0,0,0]
             best = [typemax(Float64), 0]
             for searchtype in [0, 1, 2]
-                GC.gc()
+                # stabilizes the debug timings below, but forces 180 full
+                # collections across these loops which dominates the file's GC time
+                # GC.gc()
                 tres = @timed test_getindex_algs(S, I, J, searchtype)
                 res[searchtype+1] = tres[1]
                 times[searchtype+1] = tres[2]
@@ -890,9 +892,9 @@ end
     for I in IA
         Isorted = sort(I)
         for S in SA
-            GC.gc()
+            # GC.gc() # see comment above
             ru = @timed S[I, J]
-            GC.gc()
+            # GC.gc()
             rs = @timed S[Isorted, Jsorted]
             if debug
                 @printf(" %7d | %7d | %7d | %4.2e | %4.2e | %4.2e | %4.2e |\n", round(Int,nnz(S)/size(S, 2)), length(I), length(J), rs[2], ru[2], rs[3], ru[3])