Revert of ensure host compiler is always clang when cross compiling from linux...

Revert of ensure host compiler is always clang when cross compiling from linux (patchset #6 id:100001 of https://codereview.chromium.org/955393002/)

Reason for revert:
broke some things

Original issue's description:
> ensure host compiler is always clang when cross compiling from linux
>
> BUG=
>
> Committed: https://crrev.com/56039af476797accc238dcb24c7ab926899287a0
> Cr-Commit-Position: refs/heads/master@{#26881}

TBR=machenbach@chromium.org
NOPRESUBMIT=true
NOTREECHECKS=true
NOTRY=true
BUG=

Review URL: https://codereview.chromium.org/964483002

Cr-Commit-Position: refs/heads/master@{#26882}

build/standalone.gypi

@@ -86,7 +86,6 @@
     'werror%': '-Werror',
     'use_goma%': '<(use_goma)',
     'gomadir%': '<(gomadir)',
-    'host_clang%': '1',
 
     # .gyp files or targets should set v8_code to 1 if they build V8 specific
     # code, as opposed to external code.  This variable is used to control such
@@ -334,26 +333,6 @@
           }],
         ],
       },
-      'conditions': [
-        ['clang!=1 and host_clang==1 and target_arch!="ia32" and target_arch!="x64"', {
-          'make_global_settings': [
-            ['CC.host', '<(clang_dir)/bin/clang'],
-            ['CXX.host', '<(clang_dir)/bin/clang++'],
-          ],
-        }],
-        ['clang==0 and host_clang==1', {
-          'target_conditions': [
-            ['_toolset=="host"', {
-              'cflags_cc': [ '-std=gnu++11', ],
-            }],
-          ],
-          'target_defaults': {
-            'target_conditions': [
-              ['_toolset=="host"', { 'cflags!': [ '-Wno-unused-local-typedefs' ]}],
-            ],
-          },
-        }],
-      ],
     }],
     # 'OS=="linux" or OS=="freebsd" or OS=="openbsd" or OS=="solaris"
     #  or OS=="netbsd"'