[benchmark] Add another floating point conversion benchmark

Author: xwu

benchmark/single-source/FloatingPointConversion.swift

@@ -23,6 +23,11 @@ public let FloatingPointConversion = [
     runFunction: run_ConvertFloatingPoint_MockFloat64Exactly,
     tags: [.validation, .api],
     setUpFunction: { blackHole(mockFloat64s) }),
+  BenchmarkInfo(
+    name: "ConvertFloatingPoint.MockFloat64Exactly.bis",
+    runFunction: run_ConvertFloatingPoint_MockFloat64Exactly_bis,
+    tags: [.validation, .api],
+    setUpFunction: { blackHole(mockFloat64s) }),
   BenchmarkInfo(
     name: "ConvertFloatingPoint.MockFloat64ToInt64",
     runFunction: run_ConvertFloatingPoint_MockFloat64ToInt64,
@@ -135,6 +140,11 @@ struct MockFloat64: MockBinaryFloatingPoint {
   init(_ _value: Double) { self._value = _value }
 }
 
+struct MockFloat32: MockBinaryFloatingPoint {
+  var _value: Float
+  init(_ _value: Float) { self._value = _value }
+}
+
 let doubles = [
    1.8547832857295,  26.321549267719135, 98.9544480962058,    73.70286973782363,
   82.04918555938816, 76.38902969312758,  46.35647857011161,   64.0821426030317,
@@ -181,6 +191,16 @@ public func run_ConvertFloatingPoint_MockFloat64Exactly(_ N: Int) {
   }
 }
 
+@inline(never)
+public func run_ConvertFloatingPoint_MockFloat64Exactly_bis(_ N: Int) {
+  for _ in 0..<(N * 100) {
+    for element in mockFloat64s {
+      let f = convert(exactly: identity(element), to: MockFloat32.self)
+      blackHole(f)
+    }
+  }
+}
+
 @inline(never)
 public func run_ConvertFloatingPoint_MockFloat64ToInt64(_ N: Int) {
   for _ in 0..<(N * 1000) {