Reland "win: Link with lld instead of MSVC's link.exe by default"

This is a reland of be8138a4
The issues with the previous attempt were addressed in the latest
Clang roll (#553415).

Original change's description:
> win: Link with lld instead of MSVC's link.exe by default
>
> lld is LLVM's linker. It produces PE/COFF and PDB files just like
> link.exe, but it's significantly faster and it can also handle LLVM's
> internal representation, which will enable us to do link-time
> optimization and control-flow integraty checks with Clang.
>
> While lld is much faster at linking, it doesn't support incremental
> links, meaning builds that only touch a few files and re-link a large
> executable may become slower.
>
> This is the first attempt at switching everything over, with the
> purpose of gathering data and finding unknown unknowns. It's likely
> temporary until something breaks.
>
> is_win_fastlink is implicitly ignored when using lld, as lld without
> fastlink is faster than link.exe with it.
>
> Also switch the CrWinClangLLD bots on chromium.clang to use MSVC's
> link.exe to make sure that configuration keeps working.
>
> Bug: 792131
> Change-Id: I0f115a78c33d69eadbd480f75c2a5d636e86483d
> Reviewed-on: https://chromium-review.googlesource.com/983632
> Commit-Queue: Nico Weber <thakis@chromium.org>
> Reviewed-by: Nico Weber <thakis@chromium.org>
> Cr-Commit-Position: refs/heads/master@{#551367}

Bug: 792131
Change-Id: I3b76cd015ef18bb3e2ac7a3efa4352c4f04e560b
Reviewed-on: https://chromium-review.googlesource.com/1028374Reviewed-by: Nico Weber <thakis@chromium.org>
Commit-Queue: Hans Wennborg <hans@chromium.org>
Cr-Commit-Position: refs/heads/master@{#553776}

build/config/compiler/compiler.gni

@@ -162,12 +162,12 @@ declare_args() {
   # Linux or Fuchsia.
   # TODO(pcc): Enable lld on more architectures on Linux. E.g. we probably need
   # to fix some of crbug.com/742655 to enable it on ARM.
-  use_lld = is_clang &&
-            ((is_win && host_os != "win") || is_fuchsia ||
-             (use_thin_lto && target_os != "chromeos") ||
-             (is_linux && current_cpu == "x64" && target_os != "chromeos") ||
-             (is_android && (current_cpu != "arm" || arm_version >= 7) &&
-              current_cpu != "mipsel" && current_cpu != "mips64el"))
+  use_lld =
+      is_clang &&
+      (is_win || is_fuchsia || (use_thin_lto && target_os != "chromeos") ||
+       (is_linux && current_cpu == "x64" && target_os != "chromeos") ||
+       (is_android && (current_cpu != "arm" || arm_version >= 7) &&
+        current_cpu != "mipsel" && current_cpu != "mips64el"))
 }
 
 declare_args() {

tools/mb/mb_config.pyl

@@ -114,10 +114,10 @@
       'CrWinAsan(dll)': 'asan_clang_shared_v8_heap_x86_full_symbols_release',
       'CrWinAsanCov': 'asan_clang_edge_fuzzer_static_v8_heap_x86_full_symbols_release',
 
-      'CrWinClangLLD': 'clang_tot_official_static_use_lld_x86',
-      'CrWinClangLLD64': 'clang_tot_shared_release_use_lld_dcheck',
-      'CrWinClngLLD64dbg': 'clang_tot_full_symbols_shared_debug_use_lld',
-      'CrWinClngLLDdbg': 'clang_tot_full_symbols_shared_debug_use_lld_x86',
+      'CrWinClangLLD': 'clang_tot_official_static_no_lld_x86',
+      'CrWinClangLLD64': 'clang_tot_shared_release_no_lld_dcheck',
+      'CrWinClngLLD64dbg': 'clang_tot_full_symbols_shared_debug_no_lld',
+      'CrWinClngLLDdbg': 'clang_tot_full_symbols_shared_debug_no_lld_x86',
       'linux-win_cross-rel': 'clang_tot_win_release_cross',
       'ToTAndroid': 'android_clang_tot_release_minimal_symbols',
       'ToTAndroid64': 'android_clang_tot_release_arm64',
@@ -1124,24 +1124,24 @@
       'clang_tot', 'shared', 'debug',
     ],
 
-    'clang_tot_full_symbols_shared_debug_use_lld': [
-      'clang_tot', 'full_symbols', 'shared', 'debug', 'use_lld',
+    'clang_tot_full_symbols_shared_debug_no_lld': [
+      'clang_tot', 'full_symbols', 'shared', 'debug', 'no_lld',
     ],
 
-    'clang_tot_full_symbols_shared_debug_use_lld_x86': [
-      'clang_tot', 'full_symbols', 'shared', 'debug', 'use_lld', 'x86',
+    'clang_tot_full_symbols_shared_debug_no_lld_x86': [
+      'clang_tot', 'full_symbols', 'shared', 'debug', 'no_lld', 'x86',
     ],
 
     'clang_tot_shared_debug_x86': [
       'clang_tot', 'shared', 'debug', 'x86',
     ],
 
-    'clang_tot_shared_release_use_lld_dcheck': [
-      'clang_tot', 'minimal_symbols', 'shared', 'release', 'use_lld', 'dcheck_always_on',
+    'clang_tot_shared_release_no_lld_dcheck': [
+      'clang_tot', 'minimal_symbols', 'shared', 'release', 'no_lld', 'dcheck_always_on',
     ],
 
-    'clang_tot_official_static_use_lld_x86': [
-      'clang_tot', 'minimal_symbols', 'official', 'static', 'release', 'use_lld', 'x86',
+    'clang_tot_official_static_no_lld_x86': [
+      'clang_tot', 'minimal_symbols', 'official', 'static', 'release', 'no_lld', 'x86',
     ],
 
     'clang_tot_minimal_symbols_shared_release': [
@@ -2085,6 +2085,10 @@
       'gn_args': 'use_lld=true',
     },
 
+    'no_lld': {
+      'gn_args': 'use_lld=false',
+    },
+
     'use_vaapi': {
       'gn_args': 'use_vaapi=true',
     },