Revert 203907 "Modify base_unittests.exe to use the allocator shims"

Revert 203907 "Modify base_unittests.exe to use the allocator shims"

Fails to compile:

88>allocator.lib(allocator_shim.obj) :error LNK2005: "void * __cdecl operator new[](unsigned int,struct std::nothrow_t const &)" (??_U@YAPAXIABUnothrow_t@std@@@Z) already defined in libcmt.lib(newaopnt.obj)
88>..\build\Release\base_unittests.exe : fatalerror LNK1169: one or more multiply defined symbols found

> Modify base_unittests.exe to use the allocator shims
> required to use tcmalloc on Windows.
> 
> This fixes failing SecurityTest.MemoryAllocationRestriction
> tests which are testing the tcmalloc 2Gb memory limits
> imposed for security
> 
> BUG=242304
> 
> Review URL: https://chromiumcodereview.appspot.com/15674003

TBR=wfh@chromium.org

Committed: https://src.chromium.org/viewvc/chrome?view=rev&revision=203911

[jochen (gone - plz use gerrit), 2013-06-04 10:38:19]

Committed patchset #1 manually as r203911.