[TypeChecker] NFC: Complicate perf test-case (rdar://19737632) by adding more operators

This test has become flaky in different configurations due to a varying
number of available operator overloads, let's use more operators to make
sure that it's "too complex" regardless of configuration.

Resolves: rdar://79414045

Author: xedin

validation-test/Sema/type_checker_perf/slow/rdar19737632.swift

@@ -4,5 +4,8 @@
 let a = "a"
 let b = "b"
 let c = 42
-_ = "a=" + a + ";b=" + b + ";c=" + c
+let d = 0.0
+let e: Float = 1.0
+
+_ = "a=" + a + ";b=" + b + ";c=" + c + ";d=" + d + ";e=" + e
 // expected-error@-1 {{reasonable time}}