asim: deflake TestThrashing

Previously, tsFromFunc generated 100 values using math.Sin(math.Pi *
float64(tick) / 10) to produce oscillating numbers for thrashing tests. Small
differences in the least significant digits (up to ~1e-10) can occur across
architectures due to slight variations in sin computation, but these are
negligible. This commit attempts to deflake this test by rounding the numbers
generated to 6 digits.

Author: wenyihu6

pkg/kv/kvserver/asim/history/testdata/TestThrashing/oscillate

@@ -1,7 +1,7 @@
 echo
 ----
 An example that the thrashing percentage can arbitarily exceed 200%.
-input: [0 0.3090169943749474 0.5877852522924731 0.8090169943749475 0.9510565162951535 1 0.9510565162951536 0.8090169943749475 0.5877852522924732 0.3090169943749475 1.2246467991473515e-16 -0.3090169943749469 -0.587785252292473 -0.8090169943749473 -0.9510565162951535 -1 -0.9510565162951536 -0.8090169943749476 -0.5877852522924732 -0.3090169943749476 -2.449293598294703e-16 0.3090169943749472 0.5877852522924722 0.8090169943749472 0.9510565162951535 1 0.9510565162951538 0.8090169943749476 0.5877852522924734 0.3090169943749478 3.6739403974420544e-16 -0.30901699437494706 -0.5877852522924728 -0.8090169943749472 -0.9510565162951534 -1 -0.9510565162951538 -0.8090169943749477 -0.5877852522924735 -0.3090169943749479 -4.898587196589406e-16 0.30901699437494523 0.5877852522924728 0.8090169943749471 0.9510565162951529 1 0.9510565162951538 0.8090169943749468 0.5877852522924737 0.30901699437494967 6.123233995736757e-16 -0.3090169943749451 -0.5877852522924726 -0.8090169943749481 -0.9510565162951534 -1 -0.9510565162951539 -0.8090169943749489 -0.5877852522924737 -0.3090169943749498 -7.347880794884109e-16 0.3090169943749484 0.5877852522924725 0.809016994374948 0.9510565162951533 1 0.9510565162951539 0.809016994374949 0.5877852522924738 0.3090169943749465 8.57252759403146e-16 -0.3090169943749483 -0.5877852522924724 -0.8090169943749458 -0.9510565162951533 -1 -0.9510565162951539 -0.809016994374947 -0.5877852522924739 -0.3090169943749467 -9.797174393178812e-16 0.3090169943749448 0.5877852522924695 0.8090169943749479 0.9510565162951533 1 0.951056516295154 0.809016994374949 0.5877852522924769 0.3090169943749468 1.1021821192326163e-15 -0.3090169943749447 -0.5877852522924722 -0.8090169943749458 -0.9510565162951543 -1 -0.951056516295154 -0.8090169943749491 -0.587785252292477 -0.3090169943749469]
+input: [0 0.309017 0.587785 0.809017 0.951057 1 0.951057 0.809017 0.587785 0.309017 0 -0.309017 -0.587785 -0.809017 -0.951057 -1 -0.951057 -0.809017 -0.587785 -0.309017 -0 0.309017 0.587785 0.809017 0.951057 1 0.951057 0.809017 0.587785 0.309017 0 -0.309017 -0.587785 -0.809017 -0.951057 -1 -0.951057 -0.809017 -0.587785 -0.309017 -0 0.309017 0.587785 0.809017 0.951057 1 0.951057 0.809017 0.587785 0.309017 0 -0.309017 -0.587785 -0.809017 -0.951057 -1 -0.951057 -0.809017 -0.587785 -0.309017 -0 0.309017 0.587785 0.809017 0.951057 1 0.951057 0.809017 0.587785 0.309017 0 -0.309017 -0.587785 -0.809017 -0.951057 -1 -0.951057 -0.809017 -0.587785 -0.309017 -0 0.309017 0.587785 0.809017 0.951057 1 0.951057 0.809017 0.587785 0.309017 0 -0.309017 -0.587785 -0.809017 -0.951057 -1 -0.951057 -0.809017 -0.587785 -0.309017]
   1.00 ┤ ╭╮      ╭╮      ╭╮      ╭╮     ╭─╮
   0.80 ┤╭╯│     ╭╯│     ╭╯│     ╭╯│     │ │
   0.60 ┤│ ╰╮    │ ╰╮    │ ╰╮    │ │     │ │

pkg/kv/kvserver/asim/history/thrashing_test.go

@@ -8,6 +8,7 @@ package history
 import (
 	"fmt"
 	"math"
+	"strconv"
 	"strings"
 	"testing"
 	"testing/quick"
@@ -22,9 +23,14 @@ import (
 )
 
 func tsFromFunc(ticks int, f func(tick int) float64) []float64 {
+	roundToSixDigits := func(num float64) float64 {
+		formatted := fmt.Sprintf("%.6f", num)
+		result, _ := strconv.ParseFloat(formatted, 64)
+		return result
+	}
 	vs := make([]float64, ticks)
 	for i := 0; i < ticks; i++ {
-		vs[i] = f(i)
+		vs[i] = roundToSixDigits(f(i))
 	}
 	return vs
 }