internal/concurrent: remove dependency on math/rand/v2

This change uses linkname for the one random function
internal/concurrent needs to avoid taking a dependency on math/rand/v2.
This lowers the bar to using this package.

Change-Id: I9dba1121b66ba35f56521643937f220936ea5321
Reviewed-on: https://go-review.googlesource.com/c/go/+/594057
Reviewed-by: David Chase <drchase@google.com>
LUCI-TryBot-Result: Go LUCI <golang-scoped@luci-project-accounts.iam.gserviceaccount.com>
Auto-Submit: Michael Knyszek <mknyszek@google.com>

src/go/build/deps_test.go

@@ -103,7 +103,8 @@ var depsRules = `
 	< internal/godebug
 	< internal/reflectlite
 	< errors
-	< internal/oserror;
+	< internal/oserror
+	< internal/concurrent;
 
 	cmp, runtime, math/bits
 	< iter
@@ -164,9 +165,6 @@ var depsRules = `
 	MATH
 	< runtime/metrics;
 
-	RUNTIME, math/rand/v2
-	< internal/concurrent;
-
 	MATH, unicode/utf8
 	< strconv;
 

src/internal/concurrent/hashtriemap.go

@@ -7,7 +7,6 @@ package concurrent
 import (
 	"internal/abi"
 	"internal/goarch"
-	"math/rand/v2"
 	"sync"
 	"sync/atomic"
 	"unsafe"
@@ -34,7 +33,7 @@ func NewHashTrieMap[K, V comparable]() *HashTrieMap[K, V] {
 		keyHash:  mapType.Hasher,
 		keyEqual: mapType.Key.Equal,
 		valEqual: mapType.Elem.Equal,
-		seed:     uintptr(rand.Uint64()),
+		seed:     uintptr(runtime_rand()),
 	}
 	return ht
 }
@@ -406,3 +405,9 @@ func (n *node[K, V]) indirect() *indirect[K, V] {
 	}
 	return (*indirect[K, V])(unsafe.Pointer(n))
 }
+
+// Pull in runtime.rand so that we don't need to take a dependency
+// on math/rand/v2.
+//
+//go:linkname runtime_rand runtime.rand
+func runtime_rand() uint64