[Tests] NFC: Update a couple of type-checker tests

Author: xedin

validation-test/Sema/type_checker_perf/slow/nil_coalescing.swift.gyb renamed to validation-test/Sema/type_checker_perf/fast/nil_coalescing.swift.gyb

@@ -1,4 +1,4 @@
-// RUN: %scale-test --invert-result --begin 1 --end 5 --step 1 --select NumLeafScopes %s
+// RUN: %scale-test --begin 1 --end 10 --step 1 --select NumLeafScopes %s
 // REQUIRES: asserts,no_asan
 
 func t(_ x: Int?) -> Int {

validation-test/Sema/type_checker_perf/fast/borderline_flat_map_operator_mix.swift renamed to validation-test/Sema/type_checker_perf/slow/borderline_flat_map_operator_mix.swift

@@ -1,4 +1,4 @@
-// RUN: %target-typecheck-verify-swift -solver-expression-time-threshold=10
+// RUN: %target-typecheck-verify-swift -solver-expression-time-threshold=1
 
 // REQUIRES: no_asan
 
@@ -10,8 +10,11 @@ struct S {
     }
 }
 
+// Note: One possible approach to this issue would be to determine when the array literal inside of the inner closure
+// doesn't have any other possible bindings but Array and attempt it at that point. That would fail overload of flatMap
+// that returns an optional value.
 func f(x: Array<S>, y: Range<Int>) -> [S] {
-    return x.flatMap { z in
+    return x.flatMap { z in // expected-error {{the compiler is unable to type-check this expression in reasonable time}}
         return ((y.lowerBound / 1)...(y.upperBound + 1) / 1).flatMap { w in
             return [S(1 * Double(w) + 1.0 + z.t),
                     S(1 * Double(w) + 1.0 - z.t)]