Revert of [heap] Decrease old space physical memory factor. (patchset #3...

Revert of [heap] Decrease old space physical memory factor. (patchset #3 id:40001 of https://codereview.chromium.org/2907363003/ )

Reason for revert:
Fails on other bots now:
https://build.chromium.org/p/client.v8/builders/V8%20Linux64%20-%20debug/builds/16197
https://build.chromium.org/p/client.v8/builders/V8%20Linux64%20GC%20Stress%20-%20custom%20snapshot/builds/13170
https://build.chromium.org/p/client.v8.ports/builders/V8%20Linux%20-%20arm64%20-%20sim%20-%20gc%20stress/builds/6749

Original issue's description:
> Fix tests regress-336820 and regress-678917.
>
> Execution tests regress-336820 and regress-678917 finished with error
> messages "allocation failure GC in old space requested" and "fatal
> javascript OOM in CALL_AND_RETRY_LAST". For successful execution,
> parameter max_old_space_size must be increased and this is done inside
> tests.
>
> TEST=mjsunit/regress/regress-336820,
>      mjsunit/regress/regress-678917
> BUG=
>
> Review-Url: https://codereview.chromium.org/2907363003
> Cr-Commit-Position: refs/heads/master@{#45672}
> Committed: https://chromium.googlesource.com/v8/v8/+/1550c869094c5873da9226ae9b4de7084692a857

TBR=hpayer@chromium.org,jochen@chromium.org,mlippautz@chromium.org,mstarzinger@chromium.org,ulan@chromium.org,ivica.bogosavljevic@imgtec.com,bmeurer@chromium.org,jarin@chromium.org,ishell@chromium.org,Ilija.Pavlovic@imgtec.com,Ilija.Pavlovic@imgtec.com,Ilija.Pavlovic@imgtec.com,Ilija.Pavlovic@imgtec.com
# Skipping CQ checks because original CL landed less than 1 days ago.
NOPRESUBMIT=true
NOTREECHECKS=true
NOTRY=true
BUG=

Review-Url: https://codereview.chromium.org/2917063002
Cr-Commit-Position: refs/heads/master@{#45673}

test/mjsunit/regress/regress-336820.js

@@ -25,8 +25,6 @@
 // (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
 // OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
 
-// Flags: --max-old-space-size=400
-
 assertThrows((function() {
   s = "Hello World!\n";
   while (true) {

test/mjsunit/regress/regress-678917.js

@@ -2,8 +2,6 @@
 // Use of this source code is governed by a BSD-style license that can be
 // found in the LICENSE file.
 
-// Flags: --max-old-space-size=270
-
 s1 = 'xxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxx';
 s1 += s1;
 s1 += s1;