Revert "[heap] Add prefix for young generation handling use counter"

This reverts commit 2c7f32e2.

Reason for revert: <INSERT REASONING HERE>

Original change's description:
> [heap] Add prefix for young generation handling use counter
> 
> R=​ulan@chromium.org
> BUG=chromium:693413
> 
> Change-Id: Ie8e6a5e20e904b81228b67f33c976569e305872c
> Reviewed-on: https://chromium-review.googlesource.com/445157
> Reviewed-by: Ulan Degenbaev <ulan@chromium.org>
> Commit-Queue: Michael Lippautz <mlippautz@chromium.org>
> Cr-Commit-Position: refs/heads/master@{#43319}

TBR=ulan@chromium.org,mlippautz@chromium.org,v8-reviews@googlegroups.com
NOPRESUBMIT=true
NOTREECHECKS=true
NOTRY=true
BUG=chromium:693413

Change-Id: If5d545d98f61931301ccf4166aa2acab82bdf4ca
Reviewed-on: https://chromium-review.googlesource.com/445178Reviewed-by: Michael Lippautz <mlippautz@chromium.org>
Commit-Queue: Michael Lippautz <mlippautz@chromium.org>
Cr-Commit-Position: refs/heads/master@{#43330}

src/counters.h

@@ -941,7 +941,7 @@ class RuntimeCallTimerScope {
   HR(incremental_marking_reason, V8.GCIncrementalMarkingReason, 0, 21, 22)    \
   HR(mark_compact_reason, V8.GCMarkCompactReason, 0, 21, 22)                  \
   HR(scavenge_reason, V8.GCScavengeReason, 0, 21, 22)                         \
-  HR(young_generation_handling, V8.GCYoungGenerationHandling, 0, 1, 2)        \
+  HR(young_generation_handling, V8.YoungGenerationHandling, 0, 1, 2)          \
   /* Asm/Wasm. */                                                             \
   HR(wasm_functions_per_module, V8.WasmFunctionsPerModule, 1, 10000, 51)