ci: compile with -Og where applicable.

To improve performance of check-world, and improve debugging, without
significantly slower builds (they're cached anyway).

This makes freebsd check-world run in 8.5 minutes rather than 15 minutes.

Author: Justin Pryzby <pryzbyj@telsasoft.com>
Reviewed-By: Andres Freund <andres@anarazel.de>
Discussion: https://postgr.es/m/20220310220611.GH28503@telsasoft.com

.cirrus.yml

@@ -107,7 +107,7 @@ task:
         \
         CC="ccache cc" \
         CXX="ccache c++" \
-        CFLAGS="-O0 -ggdb"
+        CFLAGS="-Og -ggdb"
     EOF
   build_script: su postgres -c "gmake -s -j${BUILD_JOBS} world-bin"
   upload_caches: ccache
@@ -201,8 +201,8 @@ task:
         CC="ccache gcc" \
         CXX="ccache g++" \
         CLANG="ccache clang" \
-        CFLAGS="-O0 -ggdb" \
-        CXXFLAGS="-O0 -ggdb"
+        CFLAGS="-Og -ggdb" \
+        CXXFLAGS="-Og -ggdb"
     EOF
   build_script: su postgres -c "make -s -j${BUILD_JOBS} world-bin"
   upload_caches: ccache
@@ -315,8 +315,8 @@ task:
       CC="ccache cc" \
       CXX="ccache c++" \
       CLANG="ccache ${brewpath}/llvm/bin/ccache" \
-      CFLAGS="-O0 -ggdb" \
-      CXXFLAGS="-O0 -ggdb" \
+      CFLAGS="-Og -ggdb" \
+      CXXFLAGS="-Og -ggdb" \
       \
       LLVM_CONFIG=${brewpath}/llvm/bin/llvm-config \
       PYTHON=python3