Revert "Disable clang tidy and metrics analyzer in tricium"

This reverts commit 04baf73b.

Reason for revert: outage is over

Original change's description:
> Disable clang tidy and metrics analyzer in tricium
>
> These machines are using the main linux pool, which is overloaded.
> See bug for more details.
>
> No-Presubmit: true
> Bug: 1133410
> Change-Id: I4b29e1d343c1dcbf46d185251db931199f06b322
> Reviewed-on: https://chromium-review.googlesource.com/c/chromium/src/+/2438852
> Commit-Queue: Stephen Martinis <martiniss@chromium.org>
> Reviewed-by: Andrii Shyshkalov <tandrii@google.com>
> Reviewed-by: Quinten Yearsley <qyearsley@chromium.org>
> Cr-Commit-Position: refs/heads/master@{#811805}

TBR=qyearsley@chromium.org,tandrii@google.com,estaab@chromium.org,martiniss@chromium.org

Change-Id: Ifed16288732733512d31f09d33d577aa4899ba41
No-Presubmit: true
No-Tree-Checks: true
No-Try: true
Bug: 1133410
Reviewed-on: https://chromium-review.googlesource.com/c/chromium/src/+/2441119Reviewed-by: Stephen Martinis <martiniss@chromium.org>
Commit-Queue: Stephen Martinis <martiniss@chromium.org>
Cr-Commit-Position: refs/heads/master@{#812217}

infra/config/generated/tricium-prod.cfg

@@ -64,6 +64,11 @@ functions {
 
 # Selections (enabled functions)
 
+selections {
+  function: "ClangTidy"
+  platform: LINUX
+}
+
 selections {
   function: "GitFileIsolator"
   platform: UBUNTU
@@ -74,6 +79,11 @@ selections {
   platform: UBUNTU
 }
 
+selections {
+  function: "Metrics"
+  platform: UBUNTU
+}
+
 selections {
   function: "MojomCommentator"
   platform: UBUNTU

infra/config/tricium-prod.cfg

@@ -64,6 +64,11 @@ functions {
 
 # Selections (enabled functions)
 
+selections {
+  function: "ClangTidy"
+  platform: LINUX
+}
+
 selections {
   function: "GitFileIsolator"
   platform: UBUNTU
@@ -74,6 +79,11 @@ selections {
   platform: UBUNTU
 }
 
+selections {
+  function: "Metrics"
+  platform: UBUNTU
+}
+
 selections {
   function: "MojomCommentator"
   platform: UBUNTU