This CL adds a mechanism that prevents the RuntimeProfiler from
triggering optimization of a function after
%PrepareFunctionForOptimization has been called. This is useful to
prevent flakiness in tests, as sometimes a function that already
got deoptimized would receive a new code object from a concurrent
compile that was triggered by a heuristic just in the right moment
for the assertUnoptimized test to fail. For example, the following
was happening:

PrepareFunctionForOptimization
[marking `testAdd` for optimized recompilation, reason: small function]
[concurrently compiling method `testAdd` using TurboFan]
[manually marking `testAdd` for non-concurrent optimization]
[synchonously compiling method `testAdd` using TurboFan]
[synchonously optimizing `testAdd` produced code object 0xAAAA - took 1.638 ms]
Runtime_GetOptimizationStatus OPTIMIZED `testAdd` (code object 0xAAAA)
DeoptimizeFunction `testAdd` with Code Object 0xAAAA
[concurrently optimizing `testAdd` produced code object 0xBBBB - took 3.377 ms]
Runtime_GetOptimizationStatus OPTIMIZED `testAdd` (code object 0xBBBB)

Bug: v8:9563
Change-Id: Ia4c846aba95281589317d43b82383e70fe0a35f5
Reviewed-on: https://chromium-review.googlesource.com/c/v8/v8/+/1763546Reviewed-by: Ross McIlroy <rmcilroy@chromium.org>
Reviewed-by: Yang Guo <yangguo@chromium.org>
Commit-Queue: Sigurd Schneider <sigurds@chromium.org>
Cr-Commit-Position: refs/heads/master@{#63343}