Adapt heap profiler test to changed GC timing.

R=machenbach@chromium.org
BUG=v8:6792
NOTREECHECKS=true
NOTRY=true

Change-Id: I878b11c6bddeca59ff49bfa88031a4ce15507e04
Reviewed-on: https://chromium-review.googlesource.com/759039Reviewed-by: Michael Achenbach <machenbach@chromium.org>
Commit-Queue: Michael Achenbach <machenbach@chromium.org>
Cr-Commit-Position: refs/heads/master@{#49261}

test/cctest/test-heap-profiler.cc

@@ -3117,7 +3117,7 @@ TEST(SamplingHeapProfilerPretenuredInlineAllocations) {
 
   // Call the function and profile it.
   heap_profiler->StartSamplingHeapProfiler(64);
-  for (int i = 0; i < 100; ++i) {
+  for (int i = 0; i < 80; ++i) {
     f->Call(env.local(), env->Global(), 0, nullptr).ToLocalChecked();
   }
 
@@ -3136,5 +3136,5 @@ TEST(SamplingHeapProfilerPretenuredInlineAllocations) {
     count += allocation.count;
   }
 
-  CHECK_GE(count, 9000);
+  CHECK_GE(count, 8000);
 }