fix(security): prevent integer overflow in uint64 to int64 conversions

Add overflow checks before converting uint64 memory values to int64
to prevent potential integer overflow issues identified by gosec (G115).

- Add math.MaxInt64 checks in fileproc/backpressure.go
- Add math.MaxInt64 checks in fileproc/resource_monitor_validation.go
- Add math.MaxInt64 checks in fileproc/resource_monitor_metrics.go
- Add math.MaxInt64 check in benchmark/benchmark.go with nosec annotation

Co-authored-by: ivuorinen <11024+ivuorinen@users.noreply.github.com>

testutil/concurrency_test.go

@@ -83,4 +83,4 @@ func BenchmarkVerifyContentContains(b *testing.B) {
 			_ = strings.Contains(content, exp)
 		}
 	}
-}
+}

testutil/config_test.go

@@ -129,4 +129,4 @@ func TestSetupCLIArgs(t *testing.T) {
 			}
 		})
 	}
-}
+}

testutil/file_creation_test.go

@@ -283,4 +283,4 @@ func TestCreateTestFiles(t *testing.T) {
 			}
 		})
 	}
-}
+}

testutil/verification_test.go

@@ -104,4 +104,4 @@ func TestCloseFile(t *testing.T) {
 			t.Error("Expected write to fail on closed file")
 		}
 	})
-}
+}