Show diffs for failed tests on Azure CI

It's currently not possible to view the "Tests" tab on Azure if
you're not signed in, so also display diffs in the log.

Closes GH-5612.

Author: alexdowad

azure/i386/test.yml

@@ -17,6 +17,7 @@ steps:
           -j$(/usr/bin/nproc) \
           -g FAIL,XFAIL,BORK,WARN,LEAK,XLEAK,SKIP \
           --offline \
+          --show-diff \
           --show-slow 1000 \
           --set-timeout 120 \
           ${{ parameters.runTestsParameters }}

azure/macos/test.yml

@@ -13,6 +13,7 @@ steps:
           -j$(sysctl -n hw.ncpu) \
           -g FAIL,XFAIL,BORK,WARN,LEAK,XLEAK,SKIP \
           --offline \
+          --show-diff \
           --show-slow 1000 \
           --set-timeout 120 \
           ${{ parameters.runTestsParameters }}

azure/test.yml

@@ -18,6 +18,7 @@ steps:
           -j$(/usr/bin/nproc) \
           -g FAIL,XFAIL,BORK,WARN,LEAK,XLEAK,SKIP \
           --offline \
+          --show-diff \
           --show-slow 1000 \
           --set-timeout 120 \
           ${{ parameters.runTestsParameters }}