FreeBSD: cfuncs_parse powl

Like on 64-bit Android and arm64 Linux, arm64 FreeBSD uses 128 bit
long doubles, which is not supported by Swift resulting in powl to fail
to import and failing the test.

swiftlang#51573

Author: etcwilde

test/ClangImporter/cfuncs_parse.swift

@@ -70,7 +70,9 @@ func test_pow() {
 // https://github.com/apple/swift/issues/51573
 // long doubles in AAPCS64 and 64-bit Android are 128 bits, which is not
 // supported by Swift, so don't test this.
-#if !((os(Android) && _pointerBitWidth(_64)) || (os(Linux) && arch(arm64)))
+#if !((os(Android) && _pointerBitWidth(_64)) ||
+  (os(Linux) && arch(arm64)) ||
+  (os(FreeBSD) && arch(arm64)))
 func test_powl() {
   powl(1.5, 2.5)
 }