tests: disable a floating point test for arm

Author: eeckstein

Diff for: test/stdlib/FloatingPoint.swift.gyb

@@ -574,6 +574,9 @@ FloatingPoint.test("Double.nextUp, .nextDown")
   expectBitwiseEqual(-prev, (-succ).nextUp)
 }
 
+// FIXME: This test is failing on armv4: SR-7159
+#if arch(i386) || arch(x86_64)
+
 %for Self in ['Float', 'Double']:
 FloatingPoint.test("${Self}.nextUp, .nextDown/nan") {
   let x = ${Self}.nan
@@ -584,6 +587,8 @@ FloatingPoint.test("${Self}.nextUp, .nextDown/nan") {
 }
 %end
 
+#endif
+
 #if arch(i386) || arch(x86_64)
 
 FloatingPoint.test("Float80/ExpressibleByIntegerLiteral") {