Don't truncate long lines in diff screens

When a change includes very long lines, they get truncated in the
side by side and unified diffs  due to 'overflow: hidden' in the CSS.

Change to 'overflow: visible' so that the user can scroll to see the
content.

Bug: Issue 5237
Change-Id: I6ca38a163dcca10e6ec24f45ba50a32580083341
diff --git a/gerrit-gwtui/src/main/java/com/google/gerrit/client/diff/SideBySideTable.ui.xml b/gerrit-gwtui/src/main/java/com/google/gerrit/client/diff/SideBySideTable.ui.xml
index 34b64a1..b2e3f43 100644
--- a/gerrit-gwtui/src/main/java/com/google/gerrit/client/diff/SideBySideTable.ui.xml
+++ b/gerrit-gwtui/src/main/java/com/google/gerrit/client/diff/SideBySideTable.ui.xml
@@ -37,7 +37,7 @@
     }
 
     .difftable .CodeMirror pre {
-      overflow: hidden;
+      overflow: visible;
       border-right: 0;
       width: auto;
     }
diff --git a/gerrit-gwtui/src/main/java/com/google/gerrit/client/diff/UnifiedTable.ui.xml b/gerrit-gwtui/src/main/java/com/google/gerrit/client/diff/UnifiedTable.ui.xml
index 973fc8f..c2cefe4 100644
--- a/gerrit-gwtui/src/main/java/com/google/gerrit/client/diff/UnifiedTable.ui.xml
+++ b/gerrit-gwtui/src/main/java/com/google/gerrit/client/diff/UnifiedTable.ui.xml
@@ -36,7 +36,7 @@
     }
 
     .difftable .CodeMirror pre {
-      overflow: hidden;
+      overflow: visible;
       border-right: 0;
       width: auto;
     }